Wheel lean causes bad nock travel, erratic paper tears, bow to be spine finicky, excessive wear on bushings and axle holes, and left and right points of impact when creep tuning. The Spot-Hogg Laser Aligner works on all compound bows providing an efficient and effective way to measure cam lean/alignment. No more eye-balling or guesstimating if your cams are tilted or misaligned. The Laser Aligner instantly shows the amount of tilt in the cams and wheels of a compound bow. Constructed of durable machined casing to last a lifetime. Simple to use and destined to become a standard tool for all pro shops and serious archers. The unique grooved design allows the laser to project a parallel light beam from any flat surface it is placed on.