Don’t trust the dodgy, inaccurate alignment hashmarks on your swingarm? Mount the Profi-Cat laser on your rear sprocket and its precise beam is projected along the chain to the front sprocket to ensure accurate alignment of the rear wheel, meaning no dog-tracking handling oddities or premature chain wear. More speed, optimized control, and longer parts–life result. A great addition to the toolbox. Keep it straight with this well made device. Storage case and batteries included.