The black single side UAP+ half cylinder (split 25-10-5, size 40mm) is the best choice for inexpensive home security installation. Created in accordance with the British Standards Kitemark, and also awarded the "Secured by Design" approval by the Association of Police Officers, the high quality 6 pin Kitemarked euro half cylinder can be fitted to any external door in order to ward off criminals that attempt to use the most popular break-in methods. BSi 1* Kitemarked Secured by Design approved Supplied with 3 keys Sacrificial cut, anti-bump, anti-drill and anti-pick Designed for locks that need to be opened or locked from one side only Ideal for garage door locks, stock room cupboard locks, broom cupboard locks etc Patented anti-bump feature Unrestricted keyway Can be keyed alike or mastersuited to Kinetica 3* cylinders and UAP rim cylinders Tested to EN1303:2005 Each half cylinder is packed full of security features, and is part of UAP's super smooth cylinders using the Chris Belcher designed anti-bump timing pin system. This very clever system uses nickel plated hardened steel key pins and driver pins, which gives the anti-drill feature we wanted to incorporate. The Patented timing pins are designed to interrupt the timing of the pins when bumped, and it is highly effective. And because we use special pins rather than trap pins, we do not have a high expense to get this anti-bump feature! The timing pins have inbuilt anti-picks, and mushroom driver pins, which makes them highly effective against picking. The cylinders also have a sacrificial cut line on them. If force is applied to the end of the cylinder in an attempt to break the cylinder to gain access, on standard cylinders, the weakest part of the cylinder is the screw hole which is in the centre of the cylinder (as there is less metal here). When force is applied, the cylinder will break away at this screw hole, making it very easy to manipulate the cylinder into opening. On the UAP Double Kitemarked Euro Cylinder, the cylinder will break away to the sacrificial cut line only, leaving the locking mechanism intact. If the cylinder is broken at this sacrificial cut line, the last 2 pins in the chamber remain in the cylinder, meaning that the cylinder can still be locks and unlocked with the key.