The Lazer Eyeálighted nock aids the crossbow hunter in following the flight of a crossbolt and determining the location of impact on an animal. The Lazer Eyeáis activated upon release of the crossbolt when the bow string compresses forward upon the arrow, which ensures the nock will illuminate each and every shot. After recovery of the arrow, the Lazer Eyeáis simple to turn off by slightly pulling the nock from the arrow of the shaft approximately 1/16". The Lazer Eyeácan be used repeatedly due to its durable construction and engineered design while offering up to 7 hours of illumination. Color: Blue.