REI Bell Traveler with Clip Grip
Here's what other sites are saying:
With a carabiner-clip handle and a shape that fits in your car or camp chair drink holder, this mug comes in handy on the trail and at the office. Double-wall, stainless-steel mug keeps 16 fl. oz. of your favorite beverage hot or cold. Spring-loaded gate allows you to easily clip the mug to any strap on your backpack. Splash-proof lid is easy to sip through while on the go; lid screws into place, ensuring it won't pop off. Non-skid pad on the bottom keeps the mug from sliding away. Stainless-steel body and liner cleans up easily.