D and D provides a wide range of products for wooden and metal door applications.
such as Stainless Steel Door Hinges, Door Locks, Lever Handles, Door Closers, Exit Devices, Door Stopers, Door Bolts and Door Accessories etc, not only door hardware but also Door Opening solution.
The D and D door set product category covers mortice locks, European profile cylinders, lever handles and hinges. Since the dimensions of all these products comply with DIN standards (DIN 18251 for mortice locks, DIN 18252 for profile cylinders and DIN 18255 for lever handles), the products are compatible amongst themselves regarding their functionality. All parts of the functional units are also perfectly aligned with each other.
A door chain, security chain, or security door chain consists of a small chain attached to the door frame, which attaches to a track on the door for security purposes. It is a type of lock that is often used along with other types of locks to secure a door.
Door chains are mainly intended to allow a person inside a structure to open the door slightly for purposes of communicating with individuals outside or exchanging small objects through the door while still preventing the individuals outside from gaining unauthorized access into the structure.
Door chains also can be set in place when the door does not need to be opened. They can only be touched from inside when the door has been opened, and therefore, if the locks on the door are compromised, a door chain may cause some delay, draw more attention, or leave more evidence of force being used when gaining unauthorized access to the structure.