All capsules made of extra durable, scratch resistant acrylic. Chemically inert. Acid- and softener-free. “crystal clear” view of the coin. Securely locking, but easy to open. The capsules with railroad rim has exact inner diameter. In this case, please use coin capsules one size biger than coin. For example, for 21mm diameter of coin should be used coin capsule with 21.5mm inner diameter. Coin сapsules with railroad rim are classic design in the production of capsules. Due to a rim on the entire capsule-it is easy to open.