Premium Materials: This Hydrapeak Insulated Tumbler with Straw is made of high quality 18/8 food grade stainless steel that makes it sturdier, more durable, and ensures the cup remains odor-free. All day Insulation: This stainless steel cup will keep your drinks COLD for up to 30 hours, and HOT for up to 12 hours using Hydrapeaks double wall insulation technology. Spill Proof Straw Lid: Our Hydrapeak stainless steel tumbler features a spill proof lid making the 25 oz tumbler ultra portable.