Instruct: Classify a given Amazon review as either positive or negative.
Query: Sucks. Save Your Money.

The rubber gasket does not stay on the glass. The minute the glass is wet, the rubber seal just slides right off the top. After I washed the glass and tried to use it, I literally coud not get the rubber to stay on - it would spring off the top of the glass all by itself. Utterly useless.