I just made it up as I went along. In all honestly, mine is mounted with very well disguised, black zip ties.

I am actually making these for customers. The chair has to be cut down using a saw , dremel...etc... Be careful NOT to saw his feet off when cutting down the chair. Also do not accidentally break off his hands while holding him down trying cut down the chair. The interior wiring also has to be cut out. I add a wiring harness and led flasher attached behind his chair. It can be mounted with custom brackets. Its a good amount of work to complete this mod. I hand paint them , as the stock color is all grey. It looks awesome and is interactive with electric chair multiball.