These are painting fixtures that I designed and printed for my own use. They work well enough that you may like them as well. Each product comes as a set of two items: one to hold a hull, and the other to hold a turret. Two different styles are available: fixtures and plugs. “Fixtures” have a rectangular base and are meant for holding single tank turrets and hulls. “Plugs” have a smaller round base and can be used alongside fixtures to mask turret sockets in the hulls of multi-turret tanks, and also to make larger fixtures to hold multiple tanks. Here is a video showing the construction of a multi-tank painting fixture using five sets of plugs.