What cam is used on the Best 40/45H mortise lock? December 16, 2014 00:39 Updated Answer C258. For C and CHB it's C293 on the outside and C258 on the inside. Applies To 45H Additional Information Related articles Commercial Hardware Mortise Cylinder Configurations for BEST 45 H and 45HW HD8000 Series FAQs What is the cam Best uses for their mortise locks? 9800/F9800 Narrow Stile Surface Verticle Rod Exit Devices Precision 2000 Series Illustrated Parts Breakout Catalog