Tiffen 49CP 49mm Circular Polarizer Description Essential for outdoor photography Deepens intensity of blue skies Reduces or eliminates glare 49mm diameter Circular construction. A circular polarizer has the same effect as a polarizer and is used on cameras with beam-splitting metering systems commonly found on autofocus SLRs. Features: Essential for outdoor photography Deepens intensity of blue skies Reduces or eliminates glare 49 millimeter diameter Circular construction Product Details: Brand: Tiffen Photo Filter Thread Size: 49 Millimeters Photo Filter Effect Type: Polarizer Water Resistance Level: Not Water Resistant Product Dimensions: 1.93"L x 1.93"W Product Dimensions: 1 x 3 x 3 inches Item Weight: 1.59 ounces Item model number: 49CP Is Discontinued By Manufacturer: No Date First Available: September 4, 1973 Manufacturer: Tiffen Country of Origin: USA