Cardboard 2x2 flips are the most widely used coin holders in the industry. Just insert a coin, fold over and staple. Our Cowen's brand holers--made with heavier (thicker) cardboard-- provide more protection for your coins than the generic Canadian-made holders sold by our competitors. The inside of Cowen's holders are lined with DuPont Mylar, the chemically most non-reactive lining available for coins. Mylar does not tear or scratch and is also the most moisture resistant film available. Mylar film is also dustproof with the lowest available permeability. Sold in bundles of 100 or cases of 3000 (30 bundles).