Check the listing for details. Cauldryn Smart Mug Replacement Lid, Spill Proof & Insulated for Smart Travel Mug. Color: Black, Condition: New. Listed at 4.99 USD. The Cauldryn Spill Proof Lid is conveniently compatible with all Cauldryn mug models. Whether you’re replacing your lid or keeping a spare, this Cauldryn Lid offers all the features you’ve come to enjoy from your current Smart Mug’s lid. To prevent the heat from your beverage escaping, the lid is insulated. Your vehicle upholstery and desk will be safe from spills with this lid’s spill proof design and rubber seal. Open and close the lid effortlessly with the textured sliding top. This lid features a slim sip opening that further prevents heat loss and directs the flow of coffee. The lid’s contoured lip on the drinking side makes it easier to drink from and prevents excess coffee from leaving the mug lid while you drink.