8500 Options 4 CL = centerline of faceplate 2nd line = centerline of faceplate opening 851M 852K Compatible with mortise locksets: Sargent (8100, 8200, 9200) CL 23/32" 18.2 Compatible with mortise lockset: Corbin Russwin (ML 2000) 23/32" 18.2 852L CL Compatible with mortise locksets: Yale (8700* & 8800), Accurate, Falcon, Kaba Ilco/Unican CL 25/32" 19.8 CL 25/32" 19.8 852M Compatible with mortise lockset: Schlage 23/32" 18.2 CL CL 25/32" 19.8 CL 23/32" 18.2 CL 25/32" 19.