With the Nockturnal Shift Lighted G Nocks, you can be confident of your shot placement, even in the darkest of timber. These superbright LED lighted nocks are powered for up to 20 hours by replaceable lithium batteries, making it easy to see your shot placement and recover errant arrows that have skipped under leaves and vegetation. Once you've retrieved your arrow, turning it off is a breeze thanks to an external on/off switch. Superstrong polycarbonate construction offers durability, plus it's waterproof and shockproof. Weight: 25 grains. Superbright LED lets you see shot placement and find errant arrows Powerful LEDs powered by replaceable batteries External switch for turning the light off when you retrieve your arrow Durable, clear polycarbonate construction Waterproof and shockproof