Nockturnal Shift Universal Strobing Red/Green Lighted Nock, 3 Pack Super Strong Clear Polycarbonate Construction Waterproof and Shockproof Easy on/off light system Color: Red/Green Strobing Compatible with various arrow types, including X, H, S, and GT arrows Weight: Approximately 25 grains per nock Over 20 hours of lithium-powered battery life Quantity: 3 pack Includes: Three lighted nocks, H bushings, GT bushings, S bushings.