Perfect replacement gaskets / rubber stoppers for your wide mouth Hydro Flask Lid. Made from high-quality, durable rubber. BPA / Phthalate / Latex – Free There are many reasons to have spare gaskets on hand. Gaskets get lost periodically. Warped or worn out gaskets can cause leaks. You may want to soak your gasket in vinegar periodically to prevents mold / mildew build-up. Always have a spare on hand! A damaged gasket (or no gasket, at all) means a poor seal, leading to a leaky bottle, defeating the point of having such a great bottle to begin with Replacement gaskets for these lids are hard to find – don’t buy a new lid, just get a new set of gaskets and you’ll never run out Please note: This is an aftermarket replacement product (produced by Impresa) meeting or exceeding the quality of OEM rings (based on in-house testing).