What is the size of the mounting bolt of the Universal Mounting Plate? February 11, 2021 18:01 Updated It is a ¼”x20 standard thread. This is compatible with all AbleNet mounting systems. Related articles Getting Started With the Universal Mounting Plate What are all the extra pieces left over on the Universal Mounting Plate? How do I install the locking knob on the Universal Mounting Plate? Getting Started With Jelly Bean Switch Can a Switch Adapted Peek-A-Boo Bear operate with a wireless switch?