Box Two Chain Tensioners ( Pick Your Color )
Box Two™ Chain Tensioners let you dial in your chain tension so it's just right. Two mounting holes provide room for ample adjustment on most frames. When used properly, Box Two™ Chain Tensioners help protect frame dropouts and keep your rear wheels locked in place where they should be.
Size: 3/8" (10mm)
Color: Black, Blue, Red & Silver
Weight: 2.5 ounces