GXP Bike Direct Installation Positive and Negative Disc Accessory for Mountain Bicycle Road Bike black

Feature: 1. Positive and negative disc, hard to drop chain. 2. The anode will form an oxide film on the aluminum surface, effectively protecting the aluminum alloy body. 3. Anticorrosion and antirust, anode treatment, longterm use will not fade. 4. Wonderful accessory for mountain bike, road bike. 5. 5 different type for you to choose, meet your different needs Specification: Condition: 100percent Brand New Item Type: Ceramic Bearing Rear Derailleur Pulley Material: Highstrength aluminum alloy + ceramic bearing Color: blackSize: 11T Diameter is about 41mm1.6in, 13T Diameter is about 49mm1.9inOptional: 32T, 34T, 36T, 38T, 40T Specification: use 45 6mm shaft guide roller Selection principle: 1. Try to choose the same size as the original gu