This Fusion/Viper/G car jig is typically used for pinning lexan bodies before painting, the jig has just enough extra clearance to set it at the top of the lexan to not have tire rub.
The side skirt and wheels can be used to mark where to cut the body as well with a sharpie for a better looking body after all the hard painting work.
The hole in the back is used to place a screw or post in for doing mass quantities of the same body in the same spot. Just set the depth you want to push the jig forward and each body should be mounted the same.
A cool customer idea(Thanks Jay Jaap from Holeshot Painting) is to drill the pin holes out the rest of the way and install a Bright LED so shine light through the holes to see the jig through an already painted body. (We have yet to test this ourselves but a very good idea in theory)