Wide mouth mason jars provide heavy duty leak proof storage. Highly shock resistant polypropylene, heavy walled mason jars are ideal for industrial waste sampling, long term storage and a variety of laboratory uses. They have standard 70mm, G-threaded necks, and screw caps with unique grip lugs and removable leak proof silicone rubber ring seal. Cap and jar are steam autoclavable at 121ºC (250ºF). Loosen cap when autoclaving.