Sony BKM31GM (BKM-31GM) 3D circular micro-polariser glasses (clip-on). Clipping easily on to the wearer's ordinary glasses, these passive circular polarising glasses are designed for use when viewing stereoscopic images on a compatible 3D monitor. They are optimised for the Sony LMD-3251MT and LMD-2451MT. Light and easy to wear, the BKM-31GM clips directly onto the top of the wearer's normal eyeglasses. It can be simply flipped up when 3D viewing is not required. The low-distortion polycarbonate lenses minimise transmission of UV light* and are designed to withstand temperature changes and shock in normal operation.