Containers are HDPE except 8, 16, 32 oz natural and white, and 83 oz natural, which are PPCO, a copolymer of Polypropylene and High Density Polyethylene. PPCO offers a product with a higher temperature range while maintaining good impact strength. Recycling code is "5" for PP and the HDPE recycling code remains "2".
Both natural and white lids, all sizes, are made of LLDPE. Linear Low Density Polyethylene is tough like LDPE and a bit more rigid like HDPE, thereby allowing for a tight fitting lid. Recycling code is 4. Designed to simplify and standardize the handling and storage of specimens. The containers are inert and cannot be attacked by formaldehyde or weak acids or bases. Will resist freezing or boiling. They have long shelf lives and are easily disposable. Sturdy enough for reuse. Easy to store, requires little space. Price includes container with lid.