The M Size AAC Switch Mounting Plate has hole pattern that allows you to mount various AbleNet Switches, Smoothie 125 switch (Pretorian Technologies), and the Optima/Optimax joysticks and trackballs (Pretorian Technologies). The back of the mounting plate has 1/4"-20 male thread that can directly connect with the Super Knuckle Arm, the Max Arm, and the Articulated Arm. The AAC Switch Mounting Plate is compatible with all the KUPOCARE AAC Switch Holder Kits and all the required mounting hardware (screws & nuts) is included.