The seal leakproof cup lid is specially design for YETI 30oz cups. Made of AS and PP material, heat-resistant, corrosion-resistant, nontoxic and no odor. Come with a sealable push-pull slider that you are no more worry about the spill of water or drinks. Extra large sip hole fits most straws, perfect for direct sipping or for a straw. It can be used as a spare lid, replace your broken or old lids when need.