Based off the weapon from Fall of Cybertron there are two versions, one with a guard to disguise the hand and one without the guard. 5mm post, now note I made this for a custom I'm doing so Idk if it will work for every figure but i figure I'd make this buyable anyway. Small - no guard, Medium - guard, Large - normal gun with 5mm post(note I haven't tested this but it should work also the ammo clips on teh side look a bit too wide but thats because the concept images I was using didn't show the other side so I forgot there was a clip on that side). This probably fits deluxe figures best and idk if ill scale it up or not because I don't have any customs planned that use larger figures. If you have any problems please let me know and I'll do what I can to fix the problem.