This is the Bar Motor Mount for use with the Great Planes / ElectriFly RimFire 28mm Outrunner motors. / / FEATURES: Steel construction / Black in color / / INCLUDES: One steel RimFire 28mm Outrunner Bar Motor Mount / / REQUIRES: RimFire 28mm motor / / SPECS: Mounting holes motor to mount: 16.3mm (.641") / Mounting holes mount to firewall: 31mm (1.2")