Features： 1、The surface is waterproofing. 2、Compatible with Shimano mid or long cage derailleur. 3、Suitable for highway or mountains. 4、The shape of cogs are specially designed for shifting performances. 5、Made of fine material. Specification： Is it difficult to change the speed of bicycle? Do you feel that it's hard to ride your bike? It is time to change the chain. Our chain is easy to install and fine workmanship. You won't be disappointed. Features: The surface is waterproofing. Compatible with Shimano mid or long cage derailleur. Suitable for highway or mountains. The shape of cogs are specially designed for shifting performances. Made of fine material. Specifications: Material: aluminum Color: silver Species: 8s 11T, 8s 12T, 8s 13T, 9s 11T, 9s 12T, 9s 13T, 10s 11T, 10s 12T, 10s 13T, 11s 11T, 11s 12T, 11s 13T (optional) Item size: 8s 11T / 9s 11T / 10s 11T / 11s 11T: 4.20 * 4.20 * 0.55cm / 1.65 * 1.65 * 0.22in 8s 12T / 9s 12T / 10s 12T / 11s 12T: 4.40 * 4.40 * 0.38cm / 1.73 * 1.73 * 0.15in 8s 13T / 9s 13T / 10s 13T / 11s 13T: 5.30 * 5.30 * 0.44cm / 2.09 * 2.09 * 0.17in Item weight: 8s 11T / 9s 11T / 10s 11T / 11s 11T: 10g / 0.35oz 8s 12T / 9s 12T / 10s 12T / 11s 12T: 11g / 0.39oz 8s 13T / 9s 13T / 10s 13T / 11s 13T: 15g / 0.53oz Package size: 8 * 6 * 1cm / 3.15 * 2.36 * 0.39in Package weight: 8s 11T / 9s 11T / 10s 11T / 11s 11T: 10g / 0.35oz 8s 12T / 9s 12T / 10s 12T / 11s 12T: 11g / 0.39oz 8s 13T / 9s 13T / 10s 13T / 11s 13T: 15g / 0.53oz Package list: 1 * Cassette cog Package List： 1 * Cassette cog