NIB NEVER Used Insulation: It features double-walled, vacuum-insulated stainless steel construction, designed to keep drinks hot for up to 5 hours and cold for up to 20 hours. Leak-Proof Design: The mug is 100% leak-proof, ensuring no spills, especially when on the go. Ergonomic Grip: It includes an ergonomic handle for a secure and comfortable hold, particularly designed for a 3-finger grip. Durability and Materials: Crafted from premium 18/8 stainless steel, it is BPA-free, non-toxic, and built for durability and rust-resistance. Convenience: The mug is designed to fit in standard cup holders and features a non-slip rubber bottom. It also has a wide mouth for easy cleaning.