Air-Tite Coin Capsule "I" White Ring Coin Holder for 40mm Coins The outside diameter of the "I" holder is 2.031" (51.58mm). Each order is for a single coin capsule coin holder with ring. Air-Tite holders are made from an acrylic plastic with a non-yellowing agent to ensure the crystal clear display your coins for any length of time. The rings are made of an inert cross-linked polyethylene which secures the coin in the holder and blocks air contamination. See our listing of currency boxes for storage and organization of currency sleeves.