Gear Review: Sea to Summit Delta Insul-Mug

Ran an oversized rubber band through hole in lid, then around the rim to make a lid retainer. No problem with staining - are you sure that stain was just not residue that would rinse out?; excellent stability; great storage space inside when not being used. Insulates perfectly for oatmeal or hot drink (not meant as a thermos!). Warms your hands; never burns. Easy to clean. Only leaks if you don't secure the lid properly. Bought one for my husband, too. It's my highly desirable luxury item and I love it.

I purchased one of these and it is a very poor item. It does not insulate as well as a cheap double walled plastic cup, it stained after a few cups of black coffee, and it leaks. Very poor design.