The best DOM lock cylinders, compared.
Top pick: DOM long-cam cylinder 30 x 40 mm – Highest score: the only listing that states a long cam, 70 mm overall, five keys and brass. No reviews, and the wrong cam for a standard case. Best value: DOM Diamant cylinder 30 x 30 mm – Lowest price in the set, about £431.56, with model 333TDIA0501 and five keys. Cam and overall length are not on the listing. Updated October 2026.
A DOM lock cylinder is a mechanical cylinder from DOM. You use it to replace a euro cylinder on a uPVC, composite or timber door, or to get a restricted key a high-street booth cannot copy. None of them prints a TS 007 star or a Sold Secure mark. None of the saved listings has a review score. Measure both sides from the centre of the fixing screw and match the cam. 30/30 is 60 mm overall. 30/40 is 70 mm, and it is not 35/35. West Police say the cylinder must not protrude. The [DOM lock cylinder buying guide](/hub/door-and-window-security/dom-lock-cylinder/sub/dom-lock-cylinder-buying-guide) checks profile, size and cam before you order. It is sold in the UK through DOM-UK and specialist locksmiths. It is not a generic euro barrel, and it is not a rim nightlatch. There is no cheaper DOM in the set.
A DOM lock cylinder is a mechanical cylinder from DOM. You use it to replace a euro cylinder on a uPVC, composite or timber door, or to get a restricted key a high-street booth cannot copy.
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Personal buying guide
Question 1 of 2
What did you measure from the fixing screw?
This brass DOM cylinder is listed at about £451.89 as a long cam, 30 x 40 mm, with an overall length of 70 mm and five keys. The title code 333tdia0503 and part number 15692 are printed, and the model name is given as a long-cam security cylinder. A long cam does not throw a standard lock case, so the listing fits only when the old cam matches and the door splits 30 mm one side and 40 mm the other. That specification is not a TS 007 3-star claim: the security-mark field is empty, and DOM’s Diamant table marks anti-snap as No. The saved listing has no star rating and no review text. The listing also records the control method as App, which a mechanical key cylinder does not provide, so treat that field as a catalogue error.
Pros
Cons
Best for: Replacing a long-cam euro cylinder that measures 30 mm on one side of the fixing screw and 40 mm on the other.
Less suitable: A 30/30 door, a standard cam, or any door that needs a stated TS 007 or Sold Secure mark.
Specifications
Common questions
What material is it made of?
The amazon.co.uk listing states the material as brass. The finish is also given as brass.
Is it weatherproof?
The listing does not say whether this cylinder is weatherproof.
Can it be re-keyed?
The listing does not say whether this cylinder can be re-keyed.
The amazon.co.uk listing is a polished silver DOM cylinder at about £431.56, sized 30 x 30 mm, with model number 333TDIA0501 and five keys in the box. That split is a 60 mm euro cylinder only when both sides of the door measure 30 mm from the fixing screw, and the listing does not state the overall length or the cam. The title says Diamant, DOM’s disc system, but the page does not print a TS 007 star, a Sold Secure mark, or an anti-snap line. The saved listing has no star rating and no review text, so there is no buyer record here of fit, finish, or whether the keys arrived as described. Material is given only as metal. It is the lower of the two 30/30 prices in this set, about £66.93 under the nickel listing, and it is the wrong part if the old cylinder is offset or the cam is long.
Pros
Cons
Best for: A measured 30/30 euro swap where you can confirm the cam on the old lock and you do not need a stated 3-star mark.
Less suitable: A 30/40 or long-cam case, a rim nightlatch, or a street door where the advice you are following asks for TS 007 or SS312.
Specifications
Common questions
What material is it made of?
The amazon.co.uk listing states the material as metal. No alloy or finish metal is named beyond polished silver.
Is it weatherproof?
The listing does not say whether this cylinder is weatherproof.
Can it be re-keyed?
The listing does not say whether this cylinder can be re-keyed.
The nickel listing is a 30 x 30 mm DOM cylinder at about £498.49, with overall length stated as 60 mm and a weight of 415 g. The title includes Diamant and the words CAM LG, and the comparison keeps that cam line as written rather than confirming a long cam. Cut resistant is a special-feature phrase on the listing, not a TS 007 or Sold Secure certificate, and the security-mark field is empty. Keys are included, but the count is not numbered, and the model number, part number and colour are blank. There is no star rating and no review text in the saved listing. It is the same nominal size as the polished listing at about £431.56 and costs about £66.93 more without a stated extra certificate.
Pros
Cons
Best for: A buyer who has already measured 30/30 and specifically wants this nickel listing after checking the cam on the old cylinder.
Less suitable: Anyone choosing on price, anyone who needs a counted set of keys, and any door that needs a stated 3-star cylinder.
Specifications
Common questions
What material is it made of?
The amazon.co.uk listing states the material as nickel alloy steel. The finish is given as nickel.
Is it weatherproof?
The listing does not say whether this cylinder is weatherproof.
Can it be re-keyed?
The listing does not say whether this cylinder can be re-keyed.
Three amazon.co.uk DOM Diamant listings were scored on whether size, overall length and cam are stated, on a printed model or part number, a numbered key count and a named finish, and on price inside this set only: about £431.56, about £451.89 and about £498.49. A higher price with no extra certificate does not raise the score. Every listing takes the same deduction for an empty security-mark field. DOM’s Diamant table marks anti-snap as No, and that is not treated as TS 007 or Sold Secure SS312. No amazon.co.uk reviews means no listing scores as if buyers had confirmed the fit. This is not a laboratory test. The highest score is the top pick. The lowest price on a usable 30/30 listing, with model 333TDIA0501 and five keys, is the best value.
Size, length and cam
35%A stated size, overall length and cam outrank a title that leaves the cam blank. A long cam scores because it is stated. The text still limits that listing to doors that already use a long cam. 30/40 is not scored as 35/35.
Model, keys and finish
25%A printed model or part number, a numbered key count and a named finish add points. Metal alone, an unnumbered “key(s)” line, and a blank model number do not.
Price in this set
20%Price is judged only against about £431.56, about £451.89 and about £498.49. A higher price with no extra certificate does not raise the score. That is why the polished 30/30 is the best value and the dearer nickel 30/30 is not.
Security mark
10%The same deduction applies to every listing for an empty security-mark field. DOM’s Diamant table marks anti-snap as No. That is not treated as TS 007 or Sold Secure SS312. A Diamant title is not scored as a 3-star cylinder.
Review evidence
10%None of the three saved listings has a star rating or a review text. No listing can score as if buyers had confirmed the fit, the finish or the keys.
You already want a DOM cylinder. The decision is which euro size and which cam match the door, and whether Diamant is the security job you actually need. Three amazon.co.uk listings cover that narrow set. None of them states TS 007 or Sold Secure, and none has a review score in the saved listing.
A DOM lock cylinder, in this comparison, is a mechanical euro-profile cylinder from DOM. It is sold in the UK through DOM-UK and specialist locksmiths. It is not a generic euro barrel, and it is not a Yale rim nightlatch. The only matching amazon.co.uk listings here are three DOM Diamant cylinders: polished 30/30 mm at about £431.56, long-cam 30/40 mm at about £451.89, and nickel 30/30 mm at about £498.49. There is no cheaper DOM Diamant in the set. Profile comes first.
30/30 is 60 mm only when both sides measure 30 mm from the centre of the fixing screw. The polished listing does not state overall length or cam. If the old cylinder is offset, or the cam is long, that parcel is the wrong part.
30/40 is 70 mm overall, with 30 mm on one side of the screw and 40 mm on the other. 35/35 is also 70 mm, and it is a different split. The outside end should sit flush, or within about 3 mm. West Yorkshire Police say the cylinder must not protrude.
Diamond in the title is the product name. DOM marks Diamant anti-snap as No. None of these listings states TS 007 or SS312. A kiosk cannot cut a restricted DOM key. If the card is lost, the replacement goes through a dealer.
Measure each side from the centre of the fixing screw before you compare the three prices. 30/30 is 60 mm overall. The nickel listing states that 60 mm. The polished 30/30 listing does not. 30/40 is 70 mm, and the long-cam listing states both the 70 mm and the cam. 30/40 is not 35/35. The outside end should sit flush with the handle or within about 3 mm, and it must not protrude. The cam decides whether the cylinder throws the case you already have.
Decide the job before you treat a DOM name as the specification. Disc security with a security card is one purchase. A TS 007 3-star anti-snap cylinder is another. DOM’s Diamant page marks anti-snap as No and publishes EN 1303:2015 code 160B0C6D. Attack grade D is the top EN 1303 grade for drilling, chisel, twisting and extraction. It is not a TS 007 star. Police advice cites a 3-star cylinder, or a 1-star cylinder plus a 2-star handle. SS312 is Sold Secure Diamond, certified on its own.
Three typical situations, each with a recommendation from this comparison.
The old cylinder is a long cam and the door splits 30 mm one side of the fixing screw and 40 mm the other. The top pick states that cam, 70 mm overall, five keys and brass, at about £451.89. It will not throw a standard lock case, and the listing does not state TS 007.
Both sides measure 30 mm and you can confirm the cam on the old lock. The best value is the polished DOM cylinder at about £431.56, model 333TDIA0501, with five keys. The listing does not state overall length or cam, and it is the wrong part if the old cylinder is offset or the cam is long.
You have already measured 30/30 and you specifically want the nickel listing after checking the cam. It states 60 mm and 415 g, at about £498.49. The title writes CAM LG without confirming a long cam, the key count is not numbered, and there is no extra certificate for the higher price.
The top pick is the DOM long-cam cylinder, 30 x 40 mm, at about £451.89. It has the highest score because it is the only listing that states a long cam, 70 mm overall, five keys and brass. There are no reviews, and a long cam is the wrong part for a standard case. The best value is the polished DOM 30 x 30 mm at about £431.56, with model 333TDIA0501 and five keys. Cam and overall length are missing, so it suits a measured 30/30 only after you have checked the old cam. The nickel 30/30 at about £498.49 states 60 mm and 415 g, and it costs more for the same nominal size with no extra certificate.
DOM long-cam cylinder 30 x 40 mm
Highest score: the only listing that states a long cam, 70 mm overall, five keys and brass. No reviews, and the wrong cam for a standard case.
DOM Diamant cylinder 30 x 30 mm
Lowest price in the set, about £431.56, with model 333TDIA0501 and five keys. Cam and overall length are not on the listing.
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 and manufacturer sources, plus the amazon.co.uk listings B077Q4LF93, B08W4N7RSV and B077PSM71X. Figures are taken from those pages and from the digest. Checked for this comparison in October 2026.
Expert source (DIY & tools): Charlie White (Charlie DIYte) (external profile) – public expert commentary used as a research source, not as a contributor to our pages.
This page contains affiliate links to amazon.co.uk (tag pcuk26-21). If you buy through them, we may earn a commission at no extra cost to you. Prices are the amazon.co.uk figures in the listings. None of these three saved listings has a review score, and this is not a laboratory test.
