The Disposable Large Capacity Polypropylene Culture Tubes are a great alternative to glass! These polypropylene tubes are cost efficient compared to glass and are able to do the same job. The tubes are reinforced and durable. They are so strong that they are unbreakable which makes them easier to handle without the worry of shattering glass. There is a reinforced ridge on the rim to facilitate handling and to reinforce the tubes. All of theses culture tubes are autoclavable.