9875/9975 Mortise lock device for all types of single or double doors, UL listed for Panic exit hardware. Devices are ANSI A156.3 – 2008 Grade 1. Fits stock hollow metal doors with 86 cutout and door stiles as narrow as 4 3/4 In. (121mm). The 9875 device has a smooth mechanism case and the 9975 device has a grooved case. The mortise lock device is non-handed except when the following device options are used: -2 (double cylinder) or SS (signal switch).