Made of acetal polymer. Disposable plastic cassettes that hold tissue specimens during processing and embedding, as well as in storage. Molded from a special high-density polymer, these patented 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. They can be opened and closed as often as necessary and will always relock securely without danger of specimen loss. Available in non-cytotoxic, non-metallic colors. The anterior writing area is slanted at a 45° angle to make the cassette more suitable to be used with certain types of cassette labeling instruments.