The BowPlane 2-Laser Bow Sq. 

Bow tuning laser with 360 degree rotation allowing you to cast a straight laser line inside the plane of your bow to get center shot, check the string and cam alignment showing your pin alignment in relation to your rest with the first ever laser that has a bow square attached to the laser tool for better limb to riser alignment. The square can be remove and insert a regular uni-nock into the back. Uses 4 AAAA batteries.