The problem with most mugs is that they take up so much space in your backpack so I think the GSI Collapsible Fairshare Mug would appeal to many backpacker. Although it seems more like a fun item, it does hold heat as well as any other insulated mug with a lid.
The 22-ounce mug collapse to a 1.7 inch thick disc which can easily fit just about anywhere in your backpack. There’s a ring at the rim that you can use to attach the mug to the outside of your pack by carabiner. It’s not the lightest mug in the world but it’s probably the smallest 22-ounce mug until another company tries to imitate the idea.
The material used for the mug is food-grade silicone which is highly durable and can handle hot food and water. The malleable silicone also makes it extremely easy to clean.
All the good aside, there is one minor flaw. It’s known that fluids tend to leak at the rim when the lid is closed. Future designs should hopefully address this problem.
Also available in blue.