New Archery Products Thunderglo Lighted Nocks - Green - NAP Thunderglo Lighted Nocks have ultra bright LED illumination and feature an easy on/off feature. Thunderglo Lighted Nocks are crafted of a polycarbonate blend with an aluminum shaft making them extremely durable for long lasting use and life expectancy. Universal collars will allow Thunderglo Nocks to fit most any arrow (G/X/H/S). Polycarbonate Blend Nock With Aluminum Shaft Bright Led Illumination Auto On When Nock Is Shot Led Stays On Until User Unclicks The Nock Universal Collars Fits Arrow Shafts (G/X/H/S)