This is the Great Planes ElectriFly Power System Brushless Motor Mount. This attaches to the firewall and the electric motor attaches to this mount.
Perfect fit for both 28mm RimFire, Outrunner and 24mm Ammo In-runner motor 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 in. (40-51mm). For small motors.
Length : 1.65 in. (42mm)
Width : 1.97 in. (50mm)
Height : 1.44 in. (36.7mm)
Weight : 1.2oz (35g)
Mounting Hole Dimensions : 1.19 in. x 1.19 in. (30.2x30.2mm)