With the characteristics of simple disassembly and assembly, convenient maintenance and installation, this buckle can helps to reduces chain breakage caused by improperly driven chain pins. When you remove the chain or clean the chain, you can pull the chain off with just one buckle, which is very convenient. It is constructed of steel material. There are multiple sizes to choose from: A, B, C, D, E. It is suitable for 6/7/8/9/10/11/12 speed bicycle chain. Item Name: Chain Buckles Material: Steel Style A: 6/7/8 Speed Style B: 9 Speed Style C: 10 Speed Style D: 11 Speed Style E: 12 Speed Features: Reusable, Portable, Durable Size Details: Style A (6/7/8 Speed) Shaft Length: 0.72cm/0.28" (Approx.) Style B (9 Speed) Shaft Length: 0.66cm/0.26" (Approx.) Style C (10 Speed) Shaft Length: 0.61cm/0.24" (Approx.) Style D (11 Speed) Shaft Length: 0.57cm/0.22" (Approx.) Style E (12 Speed) Shaft Length: 0.54cm/0.21" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 Pair of Chain Buckles