Lightweight, dependable and highly visible, with a shot-activated switch that wont turn off until reset by the archer. Made of clear plastic, the nock provides maximum light transmission and can be seen for hundreds of yards. The breakthrough design weighs 25% to 50% less than other lighted nocks. Installation requires no glue or magnets. Battery lasts up to 20 hours. Fits Gold Tip arrows with .246 ID shafts. Wt.: 20 gr. Colors: Red, Green, Blue, Pink. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Lighted Nocks.