Thunder Clash's back cannon based on the IDW "MTMTE" comic appearance. The base can be pluged into the back of truck mode as a turret. Two cannons/boosters can be cliped onto the turret with standard c-joints. The turret unfortunatel does not rotate in this design.
It is designed to fit over the "Battle Core" Optimus Prime's combiner head in bot mode, so it may not fit directly onto Motormaster/Menasor.
Tested with White Strong and Flexible.