I was always disappointed with the fact that my Classics Sideswipe figure didn't come with his iconic shoulder cannon. I also missed out on the upgrade set for this figure and Red Alert released by Beelzeboss. Using my skills as a civil engineer, I picked up Autodesk Fusion 360 and got to work on my own solution, and it's now available on Shapeways for everyone to purchase! The cannon mounts on either of Sideswipe's shoulders in the 4.1 mm hole. Be sure to raise the shoulder slides as far as they can go so that there's enough clearance between the back of the cannon and the roof on Sideswipe's back. In car mode, the cannon stores on one of the roof's available slots near the windshield. See the pictures below. The kit has two pieces: The mount with the C-clamp and the cannon itself. You may want to pinch the C-clamp portion of the mount enough to deform it to make it fight tighter on the cannon, but be careful and don't break it! My stretch goal is to finish my design for a trailer for CW Optimus Prime and Motormaster, but this may be too expensive to put on Shapeways! Please note that I'm not accepting commissions at this time.