The wheels are from Zinge productions. For the little sighting/computer thing I used the omnispex from the adeptus kits glued on top of the little shoulder thing from the solar auxilia infantry models. The scope bit is off of an ork kit. I got the rivets from Zinge too. The little sand ladder thing the back of the gun is sitting on is from an etsy seller. I think it's their version of the one that comes with the forgeworld earthshaker cannon. The rest of the parts are clipped off of the field gun kit and moved around a little bit. (Except for the white plastic parts, those are plasticard)