Review (4/5): Not a bad unit, but the 250ml is better
I purchased the 2-pack of the 250ml units, and needed a single extra unit. The 250ml are much better designed, though this still work as well. The 250ml have a lock on lid, and the plug connects under the unit. They also came with small cup to fill the units. The 300ml unit lid does not lock down and the power cord connect at the back of the unit, but they send an angled adapter so it doesn't sit correctly.