Sizing - The AlveyTech replacement tensioner is sized just right, with an 6 mm x 1.0 thread, and a 32 mm thread length. Always get what fits and stay on the trail longer Use - Our AlveyTech standard rear axle adjusting assembly is designed to retain the rear axle bolt allowing the chain tension to be adjusted to just how you like it on your Coleman mini bike Single Replacement - Make sure you buy the amount you want, plus some spare parts Manufacturer Part Number - Coleman: 42123/HS200-b The standard rear axle adjusting assembly for Coleman BT200X, CT200U Trail, and CT200U-EX mini bikes retains the rear axle bolt allowing the chain tension to be adjusted to just how you like it. If your chain is too tight or too loose, the adjustment tool will let you put it right.