Lockwood 536 Classroom KnobsetLockwood 536 Series Commercial Grade, Classroom Escape Knobset, Tulip Knob. Entrance Function Outside key locks and unlocks outside knob. Inside opened by knob at all times. Additional Information Satin chrome finish Compatible with most restricted keying systems 60mm backset standard 70mm and 127mm latches available separately Suit door thickness 32 48mm Brass latch bolt with 13mm projection Knobs and roses made of high purity zinc alloy Fire rated