This Mason Bottle Plastic Ring + Cap is a durable, reliable, rust-proof replacement ring and cap for Mason Bottle drinkware. It fits perfectly with all Mason Bottle products and snaps secure over all Mason Bottle drink tops, including Silicone Straws. Ideal for replacing or customizing existing Mason Bottle tops. Key Features Brand Mason Bottle Plastic construction described as rust-proof Durable and reliable ring and cap Fits perfectly with all Mason Bottle products Snaps secure over all Mason Bottle drink tops Compatible with Mason Bottle Silicone Straws Details Brand: Mason Bottle Product type: Cups & Drinkware Product name: Plastic Ring + Cap Material: Plastic Compatibility: Fits with all Mason Bottle products; snaps over all Mason Bottle drink tops, including Silicone Straws Frequently Asked Questions Will this ring and cap rust?The Plastic Ring + Cap is described as rust-proof. Which bottles does this fit?It fits perfectly with all Mason Bottle products. Does it work with straws?It snaps secure over all Mason Bottle drink tops, including our Silicone Straws.