OXO - Excellent customer service. After enjoying my large 24oz mug for 6 months, the lid was still leak proof, but when I pushed down the button and took a drink, it made a slurping noice. I called OXO and was told that there must be a seal problem. With no hesitation, they offered to send me a free replacement lid.
Excellent mug... Keeps Hot bev. Hot and Cold bev Cold.Excellent company - stands by their product.