Features： 1、This freewheel is made of high quality steel, high strength, anti-rust, non-deformation, wear-resistant and durable 2、Hollow out design reduces much weight to lessen the burden of long time cycling 3、It can promise smooth rotation of chain, suitable for chain ring between 11-42T 4、Designed for 10 speed bike, suitable for Shimano, SRAM 5、Easy to install and use Specification： Features: This freewheel is made of high quality steel, high strength, anti-rust, non-deformation, wear-resistant and durable. Hollow out design reduces much weight to lessen the burden of long time cycling. It can promise smooth rotation of chain, suitable for chain ring between 11-42T. Designed for 10 speed bike, suitable for Shimano, SRAM. Easy to install and use. Specification: Material: Steel Color: Shown as picture Applicable for Bike Chain Ring Range: 11-42T Suitable for Shimano, SRAM Size: Approx.17 x 4.5cm / 6.69 x 1.77in Weight: Approx. 645g Package List: 1 x Bike Freewheel Set 1 x Wrench 1 x Screw Package List：