The BCW's 2" x 2" coin holder is designed for long-term archival storage of a single coin. Made of inert, high-quality, crystal clear polystyrene that's a 100% archival plastic that will not harm unpolished coins. Designed for the current U.S. Coin Series of cents, nickels, dimes, quarters, half-dollars, small dollars, and the large dollar that's 38.1mm. The holder features a 2-piece design with a double-sided insert featuring a black side for contrast and a white side you can record information about your coin.