These are actually Weck reusable Glass Lids. Made of the highest quality glass, they contain NO BPA! (Bisphenol A), lead, mercury or cadmium.
Available in Sizes -
Small = 70mm/ 2 3/8"
Medium - 90mm / 3.54"
Large - 110mm / 4.33 ".
Perfect for using with Weck or Ball Mason jars. Keeps the fermenting fruit or vegetables from coming above the liquid.