The Blutz Wave Generator.
The Blutz Wave Generator is a machine that fires Blutz Waves. It was built by Bulma while she was under Baby's control, and it was used to turn Baby into a Golden Great Ape without a tail. Later, during the fight with Omega Shenron, Vegeta uses the same machine to advance to Super Saiyan 4, since he lacked a tail. The Generator was destroyed during the battle against Omega Shenron.
Bulma working the machine
The Generator in action