The Nockturnal FIT boasts robust, impact-resistant, transparent polycarbonate nock construction, housing a brilliant single LED activated by a patented, string-triggered, piston-driven switch. As with all Nockturnal nocks, the Fit ensures immediate, reliable activation upon string release, and can be swiftly turned off using the new Nockturnal Nock Tool, a small screwdriver, or most broadhead tips through a side opening.