Our Billet Aluminum Chain Adjuster Blocks hold the wheel precisely in place while tightening the chain and stay in position even when the axle is removed! Bolt's unique design means only one 10mm wrench is needed to make chain adjustments. Each anodized 6061 aluminum block has easy-to-read laser etched aligning marks. M8 stainless steel fasteners come with thread lubricant. Please consult the model application chart to select the correct option.