The E16 headgear has a resilient cam-lock feature that hold the face shield in place. The tensions can be adjusted for any fixed or moveable window position. It meets ANSI Z87.1-High Impact when paired with our 8150 polycarbonate face shield. The Mega Ratchet secure-fit features an easy turn knob that allows size adjustment without removing the helmet. Each turn of the ratchet knob automatically lock with 50 meshing teeth securing the position. The no-slip hold maintains the desired fit even in the most physically active jobs or extreme weather conditions. The hinged ratchet fits low on the nape of the neck and is height-adjustable for a perfect fit. The ratchet mechanism is cushioned with a thick sponge padding for long-lasting comfort. For use with all ERB shields except model #8170.