Disposable plastic cassettes hold tissue specimens during the embedding process, as well as in a storage file. Molded from a special high-density polymer, these cassettes keep specimens safely submerged in liquid and are totally resistant to the chemical action of histological solvents. The efficient flow-through slots maximize fluid exchange and ensure proper drainage. The one-piece integral lid eliminates the need for separate steel lids. Just snap apart and conveniently lock the lid into the base of the cassette. Cassettes can be opened or closed as often as necessary and always relock securely without danger of specimen loss. Large labeling areas are located on three sides of the cassette. Anterior writing area at a 45° angle. The more acute angle makes cassettes more suitable to be used with some models of cassette-labeling instruments.