Hooshion&reg; 4pcs 115mm Long Skid Landing Damping Sponge Shock Absorbing Protection Sleeves Quadcopter Skid-proof Sponge Foam Tube Black+Yellow for RC Quadcopter To ensure stable structure and avoid scratch for multicopter flight Fit for quadcopter/hexacopter Put the sponge sleeves around the landing skid, it effectively reduce the shock during landing. Suit for large scale multi-rotors with 12mm landing skids.