Know your shot placement, even in the darkest of timber with the Nockturnal Shift FIT Lighted Nocks. 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 find errant arrows that have skipped under leaves and vegetation. With an external on/off switch, once you've retrieved your arrow, turning it off is a breeze. The Nockturnal Shift FIT Lighted Nocks are made with superstrong polycarbonate for durability, plus they're waterproof and shockproof. The FIT system includes various sized bushings that allow these nocks to fit X, H, S, and GT arrows. Weight: 25 grains. Super-bright 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 FIT system allows compatibility with a variety of shaft diameters