The Nockturnal Shift Universal Easy Off Nock System with FIT Technology sets a new standard in lighted nock design. These lighted nocks offer unparalleled simplicity and reliability, featuring an external on/off switch that allows for effortless control. Just slide the switch to turn off the ultra-bright, string-activated LED light. With a durable polycarbonate casing, these nocks are both waterproof and shockproof, ensuring they withstand the toughest conditions. Boasting over 20 hours of battery life, the Nockturnal Shift FIT lighted nocks are designed to last. The patented, piston-driven contact linear switch activates the light immediately upon string release, providing instant illumination.