Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Works well within limitations

Very handy unit, especially for use when traveling. Collapses into compact package. Does not run for 20 minutes as advertised (probably a typo), but the water supply will last maybe 30 seconds - enough time to rinse your teeth pretty well. (You can quickly refill the reservoir and resume cleaning with minimum delay and inconvenience.) Big tip: although unit works well with ordinary alkaline batteries (2 AA cells) invest a few dollars in rechargeable NiMH cells as used in digital cameras; they power the irrigator for a long time with top performance and can be easily recharged. I'm buying more of the irrigators for gifts; they are inexpensive and provide a useful purpose.