Redcat Racing Electric Starter Gun - Replace your pull start with a Redcat electric starter gun and backplate. Works with most Redcat .16/.18/.21 Engines. Battery & Charger not included.Starter Gun & BackPlate for VX16 & VX18 Vertex Engines & SH18 SH21 engines (Battery and Charger NOT included) Includes 11011h12 backing plate. The backplate included has a 1 inch bolt pattern and 12mm hex bearing. Be sure to check your engine to make sure this size will fit.