Great Coin Holders for Long or Short-term storage of your coins. 2 inch square outside dimensions. Crystal Clear Polypropylene film. NO PVC - These holders with not damage or react with your coins. Square white cardboard coin holder, most commonly called Coin Flips or just Flips. You place coins in the holder, fold it over, and staple or tape it shut. The front and back of the coin is visible and descriptions of the coins can be written on the holder.