Dormakaba's Commercial Hardware QCL100 series Grade 1 heavy duty cylindrical locks deliver quality, performance, and long-term durability at a great value. When you need a reliable lockset for high traffic, heavy abuse applications, the QCL100 series offers flexible solutions with built-in security features to meet those demands. Tested to meet Grade 1 specification of 800,000 cycles. Standard clutching mechanism provides resistance to damage caused by physical force. Thru-bolt design and heavy-duty spring tension provides longer performance life and prevents lever sag. Concealed mounting screws. UL/cUL Listed (3 hours) for "A" label single-door applications (4' x 8') (1.219m x 2.438m).