LimitStyle WaterPad - A5 Flat Portable Water Bottle for Outdoor, Travel Bpa-Free 430ml

Bit awkward to drink from, but otherwise great, with no leaking so far!

Perfect size for slipping into messenger bag where a normal water bottle would be too bulky and awkward. The removable top makes this the only product of this type that can actually be cleaned. Initial use and testing shows no leaking so far, even with vicious shaking - will update if seals fail at some point.