Architectural quality UK manufactured by Imperial locks and latches made to BS EN 1634-1. Heavy duty tubular mortice latch. latchbolt operated for door knobs either side, compatible with our glass knobs. Light sprung as standard, heavy duty springing on request. Supplied in satin brass also available in all our plated finishes. The centre is the measurement where the spindle is fitted, allowing enough room for hand clearance, if you need advice please contact us.