This propeller is made of high quality Fiber Reinforced Plastics, which is extremely lightweight and durable and It is just designed for 550 RC helicopter . You can expect an increase in overall motor efficiency with this excellent propeller.<br><br>Description:<br>Fiber Glass 550mm main blades<br>Material: Fiber Glass<br>High Thrust<br>High durable<br>Extremely lightweight<br>Suit for RC 30 class helicopter &amp; 550 helicopter<br><br><br>Parameter:<br>Length: 21.6 Inch/550mm<br>Material: Fiber Glass<br>Shaft Hole diameter: 4mm<br>Product weight: 226g<br><br>Package information:<br>Package size: 55 * 5 * 1 cm / 21.6 * 2 * 0.4 in<br>Package weight: 231g / 9.6 oz<br><br>Package list:<br>1 * pair Fiber Glass 550mm main blades