MASONJAR
Mason jar
A Mason jar is a molded glass jar used in canning to preserve food. The mouth of the jar has screw threads on its outer perimeter to accept a metal ring . The band, when screwed down, presses a separate stamped steel disc-shaped lid against the rim of the jar. An integral rubber ring on the underside of the lid creates a hermetic seal to the jar. The bands and lids usually come with new jars, and bands and lids are also sold separately; while the bands are reusable, the lids are intended for single use when canning.The above text is a snippet from Wikipedia: Mason jar
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