This propeller is made of high quality Fiber Glass, which is extremely and durable and It is just designed for 600 RC helicopter . You can expect an increase in overall motor efficiency with this excellent propeller. Fiber Glass 600mm main blades Material: Fiber Glass High Thrust High durable Extremely Suit for RC 50 class helicopter & 600 helicopter Parameter: Length: 23.6 Inch/600mm Material: Fiber Glass Shaft Hole diameter: 3.8mm Product weight: 254g Package Contents: 1 x pair Fiber Glass 600mm main blades Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.