Tool Slacksetter Pro Adj 08-0674SlackSetter Pro Chain Slack Setting ToolTwo scales measure both chain slack and chain to swingarm clearance in millimeters Works on most street and dirt bike applications up to 75 mm chain slack Lightweight compact design fits easily in your tool box or road kit Made from engineered nylon with aluminum measuring scale Anodized laser etched precision measuring scale Accurately and quickly measures chain slack Refer to owner's manual for proper chain