This door handles is available in the following functions: Single Cylinder – Includes internal and external handles, deadbolt and all required locks & latches. The deadbolt is operated by a key outside and thumbturn on the inside. Double Cylinder – Includes internal and external handles, deadbolt and all required locks & latches. The deadbolt is operated by a key on both inside and outside. Interconnect – Includes internal and external handles, deadbolt and all required locks & latches. Similar to a single cylinder function the deadbolt is operated by a key on the outside and a thumbturn inside, however interconnect has an added function where the deadbolt and latch retract simultaneously when the lever or knob is turned to open the door. Please note: this function features a matching long backplate which incorporates both the handle and the deadbolt instead of being separate parts on the door. Dummy Set – Includes internal and external handles with a blank cylinder. Designed to be used on the non-functional side of double doors. High Security