What's the difference between Adventure Medical Kits Ultralight/Watertight and Mountain Series lines?

The Ultralight/Watertight series (.5, .7, .9) prioritizes low weight and a waterproof outer bag, and is the line most often cited by ultralight backpacking reviewers. The Mountain Series (Hiker, Backpacker, Explorer, Mountaineer) is heavier and bulkier but better organized into labeled compartments, includes a more comprehensive medication selection and a first-aid guide, and scales up to larger groups and longer trips.