This is the cylinder that goes on the front of the proton gun next to the front handle.
the cylinder attaches to the body viva a 1/4th screw though the back.
1 front cylinder is needed per proton gun.
this front cylinder is hollow, allowing people who want to install a vibration motor in the cylinder, freeing up room in the proton gun.
the cylinder base installs to your gun body, there is a second hole to feed your wires though.
you mount your motor in the inner selve, then slide it onto the base, the cap slides over all and is held in place by 4-40 set screw.
all anyone would ever see from the outside is a 1/16th small hole, this hole can be positioned anywhere so it is never seen.