The 4-Inch Parafilm Roll from MarketLab is a 4 inch wide roll of Parafilm M laboratory film that is 125 feet long. Parafilm M is a flexible, moldable film made of olefin and paraffin wax that creates an airtight, waterproof seal to protect contents. It can seal tubes, flasks, bottles, petri dishes, and other containers. This 4 inch wide roll is convenient for sealing a variety of containers in the lab. Parafilm M allows gas exchange so it can seal living cell cultures or lab samples that require air flow. It is autoclavable and resistant to most laboratory chemicals and temperatures from -80°C to 150°C. The 125 foot roll can provide over 1000 seals.