SUPERIOR BOWSTRING ACTIVATION: Most lighted nocks require the bowstring to slip forward within the nock slot, or push deeper into the arrow shaft. The Halo Nock doesn’t require any forward slippage during the shot, it activates only when the nock leaves the bowstring, giving you a more accurate shot. No matter how hard you place the nock, it won’t turn on prematurely. This superior design also avoids the mini-dry fire that occurs when other lighted nocks cause forward slippage of the bowstring.