This is the Great Planes ElectriFly Power System Brushless Motor Mount.
This attaches to the firewall and the electric motor attaches to this mount.
FEATURES: Perfect fit for both 28mm RimFire, Outrunner and 24mm Ammo In-runner
motors
Universal motor mounting bolt pattern insures an easy fit with any
brand of motor
Lightweight aluminum construction for added durability
Unlimited adjustability from 1.6-2" (40-51mm)
For small motors
INCLUDES: One motor support for small motors
All assembly hardware
REQUIRES: Mounting to the firewall and attaching the motor
SPECS: Length: 1.65" (42mm)
Width: 1.97" (50mm)
Height: 1.44" (36.7mm)
Weight: 1.2oz (35g)
Mounting hole dimensions: 1.19"x1.19" (30.2x30.2mm)