MJL Silicone Straw Hole Tumbler and Fermentation Lid with Rust Proof Band for Mason Jars (Charcoal Gray, Wide Mouth) Two Products in One! This lid and band for *Wide Mouth* (3" internal diameter) Mason jars is both a straw hole tumbler lid, and also a lacto fermentation lid! The 10.5mm hole will accept any of our straws, and is also the perfect size for our fermentation airlocks! Rust Proof (Almost) Band Included - Standard Mason jar rings rust, but stainless steel will not rust with normal use. Both parts are dishwasher safe! Safest Materials - Food grade silicone rubber and 304 grade stainless steel are BPA free, non-plastic materials for food contact that do not leach any chemicals. Stylish - These lids look great anywhere, whether you are taking a smoothie jar to-go, or fermenting vegetables on your kitchen counter! No Clinking Noises - Metal lids can clink against the straw, but silicone is soft and silent.