This is the Great Planes ElectriFly Power System Brushless Motor Mount.
This attaches to the firewall and the electric motor attaches to this mount.
Direct replacement for the Great Planes GPMG1041 .20-.48 (3.3-7.9cc)
and GPMG1061 .40-.70 (6-11cc) glow mounts
Perfect fit for both 35mm RimFire Out-runner 28mm Ammo In-runner
Universal motor mounting bolt pattern insures an easy fit with many
brands of motors
Lightweight aluminum construction for added durability
Unlimited adjustability from 2.1 - 3.1" (56 - 78mm)
For medium motors
Length: 2.53" (64mm)
Width: 2.18" (55mm)
Height: 2.18" (55mm)
Weight: 2.3oz (81g)
Mounting hole dimensions: 1.325" x 1.325" (33.65 x 33.65mm)