Redcat Racing Back Plate for Electric Starter Fits Vertex 0.16 & 0.18 Engine has 1 1/4" Bolt Pattern Redcat Racing Back Plate for Electric Starter fits vertex .16 and .18 Engine has 1 1/14in bolt pattern Genuine Redcat Racing Spare Parts Redcat Racing Part Number 11012H14 For troubleshooting and warranty information please contact a Redcat Racing Customer Service Specialist at 602-454-6445 or by emailing amazonsupport@redcatracing.com NOTE: Please read the User Manual before use.