This cylinder is 45mm x 55mm Total (100mm in length) Commonly known also as a pin tumbler lock or euro profile cylinder, these locks are a mechanism that uses pins of varying length to keep the lock from opening with the proper key. Yale's cylinders are easy to install either by a DIYer or a locksmith. Euro cylinders are commonly fitted to a multipoint lock or sometimes with mortice lock. They are normally used on external front and back doors, its important to fit the cylinder correctly or it will be at risk to lock snapping an other forms of attack. 3 Star Anti-Snap Platinum Euro Cylinder lock approved to high security British Standard TS007:2014 and Police Secure by Design Replacement Euro cylinder with hardened steel core and multi-layered defence solution to prevent forced access from attacks Anti-Pick, Anti-Screw, Anti-Pull, Anti-Bump and Anti-Drill components designed to resist to known attack methods on door lock cylinders Supplied with 3 Premium Yale dimple keys and key code identification card to order replacements The easiest way to immediately upgrade the security of your property, the euro cylinder can be replaced in a few minutes Suitable for use with a wide range of doors including timber, composite, UPVC, aluminium or patio doors with a Euro profile Each cylinder comes with 3 Yale patented keys and an identification code for easier replacement The locks are Secured by Design and BSI approved to ensure maximum protection Supplied with 3 Keys How to measure your lock (Pleas see Images) Measurement A - Measure from one end of the cylinder to the middle of the central screw hole. Measurement B - Measure from the other end to the middle of the central screw hole. Now check your measurements: Measure the overall cylinder length from end to end. The length of the cylinder should equal the sum of measurements (A) and (B) when added together. For example: If measurement (A) = 40mm and measurement (B) = 40mm the size required would