Item Type: Bike Rear Derailleur Pulley_x000D_ Material: Aluminum Alloy Frame + Steel Bearing_x000D_ Weight: Approx. 24g/0.8oz_x000D_ Applicable Model: for 4/5/6mm / 0.16/0.2/0.24in Axis, with Rear Derailleur Pulley Screw 1Reliable Material: This rear derailleur pulley is made of aluminum alloy, which is sturdy, durable, anti rust, and corrosion resistant. 213T Rear Derailleur Pulley: 13 teeth rear derailleur pulley, CNC machining, built in bearing, very lubricated. 3Applicable Model: Widely compatible performance guide wheel are equipped with 4mm/0.16in axis, 5mm/0.2in sleeve tubes, rear derailleur pulley screw. 4Rear Derailleur Pulley Support: Ensure the stability and durability of the disc work, reduce the deflection, strong support, not easy to deform. 5Rear Derailleur Pulley Edge: Further reduce the weight and increase the contact area between the guide wheel and the air. 6Large Hollow Design: The hollow edge increases dics friction system, which helps to quickly remove the sediment and rain, and increase the smoothness of riding.1 xRearDerailleurPulley 2 x Sleeve Tube