Easy to change cylinders. Usually operates a night latch on the inside of the door. Comes in a variety of security levels from basic through to high security.

Mortice Dead Lock. Found on many wooden front doors. Comes in a variety of different levels of security from basic through to 5 lever BS insurance approved.

Similar to the Mortice Dead Lock however combines a handle and spring latch. Available as 5 lever British Standard Insurance approved model.

Found in Upvc, composite and modern apartment doors. Easy and inexpensive to change the cylinder when new locks are required.