For residential and multi-family hall/closet doors. Both knobs are always unlocked. DOOR THICKNESS: 1-3/8" to 1-3/4". LATCH: 1" x 2-14", radius corner faceplate, 7/8" housing diameter, 1/2" throw, with Triple-Option square corner and circular corner faceplate. STRIKES: Dual strikes 1-5/8" x 2-1/4", radius corner and square corner, full lip, no box. BACKSET:Dual backset latches, fits either 2-3/8" or 2-3/4" backsets.