Marks 7400E/32D Satin Stainless Steel US32D Left Hand Grade 2 Office Thru-Bolted Contempo Knob Plate Mortise Lockset, specially designed with a 2-3/4" backset, a 1-1/4" x 8" wide front face plate, a anti friction latch, and an auxiliary latch. This lock set operates by key on the outside, and by turning the knob on the inside ( NO thumb turn on inside trim plate).

Office (E Function) Mortise Lockset: Latchbolt retracts by knob from either side unless outside is made inoperative by stop button in front (rocker switch). When outside is locked latchbolt is retracted by key on the outside or by knob on the inside. The auxiliary latch deadlocks the latchbolt when the door is closed (so you can't open the lock by sliding a card between the lock and the door frame). Inside knob is always free for immediate egress.