Our Stainless Steel Insulated Coffee Mug's size is 15oz, and its material is Stainless Steel. This coffee tumbler is made of stainless steel which has better corrosion resistance and thermal insulation effect than normal stainless steel. It's taste-free, rust-proof, and BPA-free. It has better quality than most stainless steel tumbler on the market. Comes with an airtight silicone seal which makes sure the travel cup 100% won't leak. It keeps hot for 6 hours and cold for 12 hours. 15oz is just perfect size to carry, with a hand lanyard. Cute shape and colorful design, very attractive. It's a good promotional gift.