[Perfect Replacement Cover：Our replacement glass lids are compatible with 30 oz tumblers to avoid purchasing the wrong size lid please measure the inner and outer diameter of your cup before purchasing Safety Materials: Made of AS and PP BPA free lightweight yet strong enough durable enough to be reused for years Easy to Use: The sliding button for replacing the lid allows you to choose between drinking straight or using a straw. It has good airtightness allowing the beverage to maintain low or high temperature for several hours Unique Design: The magnetic sliding lid is designed to be easily removed allowing you to easily clean the lid in the dishwasher. The clear lid allows you to check if a refill is needed while ensuring your drink is safe to drink After sales service: If there are any problems with our glass cup caps please feel free to contact us and we will solve them within 24 hours]