The best Isotronic marten deterrents, compared.
Top pick: Isotronic 78440 12 V car ultrasonic – Highest score: 4.1 from 140 reviews, 12 V with a vibration cut-out, CAN-bus stated in the title, at about £25.61. No UK review text in the notes. Best value: Isotronic 84025 downpipe spike belt – Lowest shelf price, about £17.92, two stainless strips and no battery, at 4.0 from 47 reviews. It does not protect an engine-bay loom. Updated October 2026.
A marten deterrent is what you buy to keep animals off a parked car, a loft, a garage, a downpipe or a tree. In Britain the animal in an engine bay is usually a mouse or a rat. The stone marten that chews wiring is a continental species. Britain's pine marten is protected, so a product name is not permission to disturb a den. Two mechanisms share the search. A high-frequency box is a sounder, sometimes with a flash. A stainless spike belt is a barrier for a pipe, a gutter or a trunk. A sounder does not close a pipe, and a belt does not cover a loom. Match the mechanism to the place before you choose a battery or a 12 V lead. A square-metre figure is the seller's claim, not a reading inside insulation. Bands around 12–24 kHz are only partly ultrasound, and some people hear a whistle. If you cannot identify the ignition circuit, a garage should make the 12 V connection. Species, place and power are set out in the [marten deterrent buying guide](/hub/pest-control/isotronic-marten-deterrent/sub/isotronic-marten-deterrent-buying-guide).
A marten deterrent is what you buy to keep animals off a parked car, a loft, a garage, a downpipe or a tree. In Britain the animal in an engine bay is usually a mouse or a rat.
18 products checked · 47 hrs invested · +14,800 readers
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Personal buying guide
Question 1 of 2
Where is the problem?
The Isotronic 78440 is a 70 g module, 8.8 × 5.7 × 2.3 cm, that wires to a 12 V car battery and prints a 40 m² range on the listing. Across 140 amazon.co.uk reviews the line is 4.1, the highest star average here, although the review notes contain no UK review text. European reviews describe cable damage stopping for months when the wiring is right, and one Belgian note says the unit switches off once the engine vibrates. The same sample includes a failure after a single night, habituation after two days, and a German comment that mice ignored a unit placed beside them. Fitting uses a third wire to terminal 15, and French reviews treat that as a garage job. The title says the module is CAN-bus compatible, yet the instruction still puts the grey lead on the terminal-15 fuse. A French reviewer heard a whistle that the writer of that review did not, which fits a 12–23 kHz band that is only partly ultrasound.
Pros
Cons
Best for: You will wire it to a 12 V battery you can reach, or a garage will, and the job is mice or rats in a car you actually drive.
Less suitable: You will not open the electrics, the battery sits in the boot on a lead of about 100 cm, or the animal might be a pine marten, a bat or a hazel dormouse.
Specifications
Common questions
Does it need a third wire to the ignition circuit?
Listing questions ask about professional installation. EU reviews in the notes describe a third wire to terminal 15 and say routing differs by car.
Does it switch off when the engine runs?
Bullets say it switches off again when there are engine vibrations, to save the battery.
Is it only for martens?
The title targets martens. The target-species field lists mouse and rat, and EU reviews disagree on mice versus martens.
Model 84025 is two V2A stainless spike strips, 160 g together, for downpipes, gutters or trees, with no battery and no ultrasound. At about £17.92 it is the lowest shelf price here, with 4.0 from 47 amazon.co.uk reviews, a thinner sample than the electronic rows. A UK review calls it useful against cats once the bands are shaped before the wire arms go in, and calls the assembly fiddly. Another UK review simply says the product is useless. Notes from German reviews mention cable ties that break when tightened and end caps that feel easy to slip off. The listing says a tree of 50 cm circumference or more needs extra strips. End caps do not make injury to a cat impossible, and the belt does nothing for a chewed loom under the bonnet.
Pros
Cons
Best for: Animals are climbing a downpipe, a gutter or a tree under 50 cm around, and you want a physical barrier rather than a sounder.
Less suitable: The damage is on cables under the bonnet, or a cat, pine marten, bat or hazel dormouse could be injured or disturbed.
Specifications
Common questions
Is it weatherproof?
Bullets call the hold durable and weatherproof. The listing asks about weatherproofing but does not add a separate answer field.
How fiddly is assembly?
A positive UK review calls assembly fiddly and advises shaping the bands before inserting the wire arms.
Will one strip fit every tree?
Bullets say tree circumferences of 50 cm or more need several strips.
The Isotronic 78580 is a 14 × 7 × 3 cm box at about £32.45 that runs on four AA cells or a car-battery lead, with an LED flash about every 60 seconds and a stated 12–24 kHz band. It carries the largest review count here, 3.8 from 320 amazon.co.uk reviews. The UK note is a single review that reported no effect on rats and squirrels after more than a week. The listing marks the product as not electric while the bullets offer a car-battery connection, so the power story is split on the same page. The UK bullets do not mention a vibration sensor, although a separate 78580 manual describes one and quotes about 60 m² indoors against the listing’s 40 m². Loft and shed questions on the page are left unanswered. Treat the 320 reviews as a count on this listing, not as proof a bay will clear.
Pros
Cons
Best for: You want one box that can sit on cells in a garage or move onto a car lead, and you accept that the UK listing does not repeat the manual’s sensor line.
Less suitable: You need a vibration cut-out printed on the amazon.co.uk bullets, or you are trying to move squirrels.
Specifications
Common questions
Can you run it from the car battery?
Bullets offer 4 AA batteries or connection to the car battery. The listing marks Is Electric as No.
Does the listing answer loft or shed use?
The listing asks about a loft and a shed but does not answer those questions in the notes.
What do UK reviewers say about squirrels?
One UK review in the notes says no effect on rats and squirrels after over a week.
The green twin pack is two ABS units, each 11.5 × 7 × 3.5 cm, running on six AAA cells with a claimed eight months of continuous use. A vibration sensor is stated to switch on about 60 seconds after the car is still, and the listing claims 40 m². The shelf price is about £45.28, the dearest row here, with 3.8 from 140 amazon.co.uk reviews. UK reviews describe fewer mice after the bay was cleaned and the units were fitted on driveway cars, plus one attic install. The same UK sample includes a pack in which only one of two units worked, followed by a half refund, and screws too small for a household screwdriver. Cable ties and screws are stated in the box. Two speakers cover two zones. They are not a doubled 12 V module.
Pros
Cons
Best for: You want two battery units for a driveway car and a second zone such as a garage, and you will not wire the car battery.
Less suitable: You expect both units to arrive working, or you need a single 12 V module with a CAN-bus line on the title.
Specifications
Common questions
What happens if one unit fails?
A UK review says only one of two worked and the seller refunded half the price.
Can you open the battery compartment easily?
A UK review could not find a screwdriver small enough for the battery screws.
Does it suit a car on the driveway?
UK reviews describe engine-bay use on driveway cars and report fewer mice after cleaning and installing the units.
This Isotronic box is 8.5 × 5.5 × 3.2 cm and 57 g, with a vibration sensor, an LED flash about every 60 seconds and a claimed 60 m². The amazon.co.uk line is 3.6 from 183 reviews, the lowest star average here, at about £31.18. A UK review says the battery screws, including the middle two, are too small to undo without a jeweller-sized driver, so the cells may never go in. Another UK review says mice were still visiting the car nightly. The listing leaves the cell type unstated and marks the product as not electric, while the bullets describe a cut-out that saves the battery when the engine runs. The 60 m² figure is the seller’s claim, not a measurement under a bonnet. The small body is the practical plus. Getting the cover off is the practical stop.
Pros
Cons
Best for: You want a small battery box with a stated vibration cut-out, and you already have a driver small enough for the cover screws.
Less suitable: You need a documented cell type before you order, or mice have already ignored a similar box in the same car.
Specifications
Common questions
Are the battery screws a known issue?
A UK review says the screws are too small to install batteries, including the middle two.
Did UK buyers stop mice in the car?
One UK review says mice still visit nightly. Another mentions the small size but not success.
How often does the LED flash?
Bullets say a bright flashing light activates every 60 seconds alongside the acoustic deterrent.
Five amazon.co.uk listings are on this page. The score follows the listing star line, adjusted where the review count is thin. There is no laboratory test of whether a box clears a bay. The top pick is the highest score: the 12 V module at 4.1 from 140 reviews. Best value is the lowest shelf price, the stainless spike belt, which is a barrier rather than a sounder. A square-metre claim is not treated as a measurement under a bonnet. Listings that disagree with themselves are marked down.
Stars with review count
30%amazon.co.uk stars count only with the review count on that listing. The 12 V module leads on stars at 4.1 from 140. The spike belt is 4.0 from 47, a thinner file, so that line does not outrank the larger electronic counts.
Power match
25%A driven car with a battery you can reach suits a 12 V lead and a vibration cut-out. Cells suit a car you will not wire. A battery in the boot is a poor match for a short lead. A listing that says not electric while the bullets offer a car battery is marked down.
Mechanism for the place
25%A sounder does not block a downpipe. A spike belt does not cover a loom. Ultrasound-and-flash boxes and the stainless belt are scored for different jobs, not as substitutes.
Listing consistency
20%Points come off when the cell type is missing, a vibration sensor appears only in a separate manual, the frequency band is absent, or loft and shed questions on the page are left unanswered.
Start with the animal and the place, then the mechanism, then the power. A UK driveway car with droppings is a rodent job. A pine marten den, a bat roost or a hazel dormouse nest is a legal stop. A sounder does not block a pipe, and the spike belt does not protect a loom. Shelf prices captured here run from about £17.92 to about £45.28. The top pick is the 12 V module with the highest star line. Best value is the stainless belt, the lowest shelf price. Nothing on this page is a lab test.
An Isotronic marten deterrent on amazon.co.uk is either a small high-frequency box for a car, loft or garage, or a stainless spiked belt for a downpipe. UK buyers are usually trying to stop mice or rats in a parked car, not a stone marten. The stone marten is the continental engine-bay species. Britain's marten is the protected pine marten. Bird scarers and plug-in room devices are a different purchase.
A bird scarer is a different product. The job on a UK driveway car is usually mice or rats. A square-metre claim on a sounder was not measured inside a muffled engine bay.
The 78440 instruction asks for a scent wash before fitting. UK reviews on the compact box and the twin pack both say the battery screws are too small for a household screwdriver. Forcing them can leave the cells out.
A loft that may hold bats is the wrong place for a sounder. A pine marten den is a legal stop, not a product choice. Spikes on a downpipe can still injure a cat.
A UK driveway car with droppings is a rodent job. A pine marten den, a bat roost or a hazel dormouse nest is a legal stop, not a listing to choose between. Ultrasound-and-flash boxes do not block a pipe. The 84025 belt does not protect a loom. Match the mechanism to the place before you compare star lines. In this comparison, four listings are electronic sounders and one is two V2A stainless strips. The belt is the purchase when animals climb a downpipe, a gutter or a tree.
Power is 12 V with an ignition cut-out on the 78440, cells with a vibration cut-out on the twin pack and the compact box, or 4 AA cells or a car battery on the 78580. A hybrid with the 12 V battery in the boot is a poor match for a long lead. The 78440 instruction quotes about 5 mA, a grey lead to terminal 15 and a 0.2 A fuse, and it asks for authorised personnel. Listings quote 12–24 kHz, and the 78440 instruction quotes 12–23 kHz. That is only partly ultrasound. Reviews mention a whistle.
Three typical situations, each with a recommendation from this comparison.
You have already found mouse nesting in the bay, and you can wire a 12 V battery or a garage will. The Isotronic 78440 is about £25.61, with 4.1 from 140 reviews, a vibration cut-out and CAN-bus stated in the title. The review notes contain no UK review text, and European notes include a failure after one night. Leave it if the battery sits in the boot on a short lead.
Cats or wildlife are using a downpipe, a gutter or a tree, and you want steel rather than a sounder. The Isotronic 84025 spike belt is about £17.92, two V2A strips, with 4.0 from 47 reviews. A UK review calls assembly fiddly. It does nothing for a chewed loom, and spikes can still injure a cat.
You want two battery units for a driveway car and a second zone, and you will not open the electrics. The Isotronic twin pack is about £45.28, six AAA cells, with 3.8 from 140 reviews. UK notes describe fewer mice after a clean and a fit, and also one dead unit in the pair. Skip it if you need a single 12 V module.
The top pick is the Isotronic 78440 12 V car ultrasonic, at about £25.61. It is the highest score: 4.1 from 140 amazon.co.uk reviews, a vibration cut-out when the engine runs, and CAN-bus compatibility stated in the title. The review notes contain no UK review text. European notes describe months without new cable damage when the wiring is right, and also a failure after one night and habituation after two days. The best value is the Isotronic 84025 downpipe spike belt, at about £17.92, the lowest shelf price here, with 4.0 from 47 reviews. It is a physical barrier for a pipe, a gutter or a tree, not a cover for a loom. None of these scores is a laboratory test, and a square-metre line is the seller's claim.
Isotronic 78440 12 V car ultrasonic
Highest score: 4.1 from 140 reviews, 12 V with a vibration cut-out, CAN-bus stated in the title, at about £25.61. No UK review text in the notes.
Isotronic 84025 downpipe spike belt
Lowest shelf price, about £17.92, two stainless strips and no battery, at 4.0 from 47 reviews. It does not protect an engine-bay loom.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Public UK sources used for this comparison. Shelf prices, stars and review counts are the amazon.co.uk figures captured for these five listings. Last checked 20 October 2026.
This page contains affiliate links to amazon.co.uk. If you buy through them, we may earn a commission at no extra cost to you. Prices, stars and review counts are the UK listing lines captured for these five products. We did not run a laboratory test.
