Master Lock BCO0415 biscuit knob style passage door lock. Satin nickel finish. Six way adjustable latch fits all doors 2-3/8-inch or 2-3/4-inch backset, square, rounded corners or drive in.The SilvaBond antimicrobial protected finish on this Biscuit Knob Hall and Closet Lockset has proved to be very effective in controlling bacteria, mold and mildew on surfaces. Independent laboratory testing has confirmed the effectiveness of this long lasting and durable finish.