For residential single and multi-family bed/bathroom doors Pushbutton locking, opens from outside with small tool; turning inside knob releases pushbutton 1 piece knob for increased security Solid brass trim and all metal parts 3 piece assembly DUALOPTION UNIVERSAL: Fits all doors; 2-3/4 or 2-3/8 backset; 1-1/8 square corner, 1/4 round corner, or circular drive-in preps OPTION UNIVERSAL: Fits all doors; 2-3/4 or 2-3/8 backset; 1-1/8 square corner 1/4 round corner or circular drive-in preps.