Thumb-turn euro cylinders offer the ideal security solution. The door can be locked and unlocked from the inside without the use of a key but without diminishing the level of security. This type of lock is also ideal in case of fires. If you have locked your door and could not find the key to get out in case of an emergency, what would you do? These replacement thumb-turn cylinders enhance the security of your door and are so easy to fit that any DIY novice can do it in minutes!