[Durable Material]:Made of Metal material. Our Bike Single speed conversion kit is lightweight but durable, anti-corrosion and anti-rust. Compatible with the chain width from 1/2 inch x3/32 inch to 1/2 inch x11/128 inch . (6 speed to 11 speed chains).[Compatable with]:Single speed conversion kit sizes: 18T. Suitable for racing bikes, road bikes, mountain bikes. Compatible with for and Sram Hubs.[Chain Size]:Convert a multi speed hub to single speed wheel. Compatible with all or sram 7 to 10 speed cassette type hub body. (Compatible with for 1/2 inch x 1/8 inch and 1/2 inch x 3/32 inch single speed chains)NOTE: It will NOT covert the hub into fixie, so the hub is still a freewheel hub.With it, you can ride your bike more happily, make you love the sport more, and be more suitable for road, cross-country, mountain bikingMaterial:Metalcolour:Black + SilverPackage Contents:1 * flywheel1 set * flywheel cover4 * spacersOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.