Feature:1. Reliable Material: This rear derailleur pulley is made of aluminum alloy, which is sturdy, durable, anti rust, and corrosion resistant.2. 13T Rear Derailleur Pulley: 13 teeth rear derailleur pulley, CNC machining, built in bearing, very lubricated.3. Applicable Model: Widely compatible performance guide wheel are equipped with 4mm/0.16in axis, 5mm/0.2in sleeve tubes, rear derailleur pulley screw.4. Rear Derailleur Pulley Support: Ensure the stability and durability of the disc work, reduce the deflection, strong support, not easy to deform.5. Rear Derailleur Pulley Edge: Further reduce the weight and increase the contact area between the guide wheel and the air.Specification:Item Type: Bike Rear Derailleur PulleyMaterial: Aluminum Alloy Frame + Steel BearingWeight: Approx. 24g/0.8ozApplicable Model: for 4/5/6mm / 0.16/0.2/0.24in Axis, with Rear Derailleur Pulley Screw Package List:1 x Rear Derailleur Pulley 2 x Sleeve Tube