Barnett Headhunter strobe lighted nocks enhance shot visibility in low-lighting. Strobing light assists in finding arrow and provides visibility to where shot placement occurred. The multicolored strobing lights alternate between multiple color patterns, 'pulse', 'fade', and 'flash' which enhance visibility of the arrow once it has been shot. Strobe lighted nocks are easily controlled with an on/off switch. The lighted nocks are designed to fit .300” inner diameter crossbow arrows. BARNETT: The most trusted name in crossbows since 1962.