The LIT Lighted Arrow Nocks are designed to make tracking your arrow effortless, fitting most carbon shafts with an ID of 0.166". Each nock features an external on/off switch for easy activation without tools, and automatically lights up when the arrow is shot, making it visible both day and night. With a long-lasting battery that stays lit for up to 48 hours, these nocks come in a variety of colors, including red, blue, green, yellow, or multi-color, and are a cost-effective way to preserve expensive arrows. Each pack contains three lighted nocks, weighing 16 grains each.