Easily Slip into the lens holes and lays flush to the front surface of the lens. Prongs located on the end pieces. As they set, tension holds the lenses in place. Their flanges keep them secure. No screws means there is less hassel in production of lenses. Our 1.6mm Plastic Mounting Sleeve are designed to fit all modern frames. Made of high quality material
Unit: Package of 50 Mounting Sleeve