The ProMaster Digital HD UV Filter is an extremely high quality UV filter designed to protect your lens and to filter excess ultraviolet light. Constructed with premium Schott glass and 12 layers of anti-reflective coating, these filters are designed to yield extreme image sharpness. They also feature a precision machined, super slim aluminum frame with anti-reflective matte finish and kurled edges.Premium Schott optical glassL39 UV coating12 layer anti-reflective coatingPrecision aluminum ring with matte finsish and knurled edges