These weights are actually Weck reusable Glass Lids. Made of the highest quality glass, they contain NO BPA! (Bisphenol A), lead, mercury or cadmium.
Weck glass jar lids are the only preserving lids in the world that can be reused thousands of times and the only glass certified as lead free.
Lids come in 3 sizes: small, medium and large. Small = 70mm, Medium = 90mm, Large = 110mm.