This A40 series motors are designed for 3D-Aerobatic up to 6 pounds and Scale models up to 8,8 pounds using 3 to 6 series LiPoly batteries. The 14-pole Outrunnermotor type design creates MASSIVE TORQUE, therefore larger direct drive props can be used without the need for a gearbox. This motor features Oversize bearings, Curved Neo-magnets and High efficiency stator design. Backmount, Prop adapter and all screws are included. For mor info go to : www.hacker-motor.com/images/Catalog09/Hacker-2009-WEB%2012+13.pdf