Features : 

High quality aluminum material.
Suitable for brushless motors and speed controllers.
Delicate workmanship.

Specifications : 

Color : Silver
Material : Aluminum
Motor Axle hole diameter : 3.17mm
Output shaft diameter : 5mm
Size : 2.7 x 1.2cm(L * D)
Quantity : 1 Pcs

Package included : 

1 x RC Aluminum Bullet Propeller Adapter Holder