The quality of a lock is judged by how easy it is to prevent unwanted access. However, there are situations where the presence of a lock can represent a problem even for those who are authorised to gain access. This is especially the case where you need to quickly gain access to a house or a room to rescue a person closed inside who is unwell and unable to open the door. Indeed, with common double cylinder locks, if the key has been left inserted in the keyhole inside the house one is often unable to open the door from the outside, even having another correct key. To avoid this situation, which can result in the loss of valuable time in the event of an emergency, there are cylinders designed specifically to be opened (with the key!) from the outside even if a key has been left inside. Continue reading →