Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Surprising for what it is

I found this for $5 at a thrift store and brought it home. The battery was at the end of it's lifespan but everything else seems to be fine. I don't like how this particular model leaks so much air into the dust cup around the edges rather than pulling all the air through the brushroll area. The model I purchased has a flat, slide-out filter. I think later models have been redesigned and perhaps they seal better.Now for the "don't try this at home" section... I hooked up a cord to this with a cigarette lighter plug like is used in cars, and ran it on 12 volts rather than 6 volts. That's double the voltage! I made sure to get the polarity correct. This thing draws a lot of amps at 12 volts and the cord needs to be fairly heavy. But you should see the vacuuming performance! It's still not too loud, at 12 volts. I could see using this as a vacuum in an RV, or in a cabin with a 12 volt solar power system.