This 1.75 inch Halo Shield is made of a lightweight and durable plastic that easily slides onto the Night Eyes HL08 Headlamps (will NOT fit the HL50 or the HL50-Q Headlamps). The Halo Shield helps keep unwanted peripheral light from shinning in the scope and from reflecting off of your hunting partner and equipment. It also fits WF-501B, 501B, and ML-103B flashlights.