Mason Jars, polypropylene with white polypropylene screw closure. These durable jars have 70-mm necks which take fixtures or closures with Mason jar threads. Can also be used with Osterizer® and other blenders with Mason jar threads. Like NALGENE® bottles, these jars have a neck ring for shrink seal. Also handy for fluid transfer in the lab or field when used with NALGENE® fluid-transfer closure. Refer to that product description for guidelines. NOTE: Before autoclaving, just set cap or closure on top of the container without engaging the threads.