Air-Tite coin capsules offer crystal clear acrylic protection for your coin collection. The ring fit system that Air-Tite created will accommodate all U.S. coins and most world coins between 13 mm and 43 mm, and in some cases up to 65 mm. This makes them ideal for odd sized and unusual coins. Ring fit holders contain a foam ring that is placed into the coin capsule. The rings are made from a material called volara and are free of PVC. The ring’s purpose is to provide a framing around the coin to accommodate most odd coin sizes, but also provides an aesthetic contrast between the coin and the ring in presentation.