Instruct: Classify an Amazon review as either positive or negative.
Query: travel mug doesn't really work

I purchased this item as a Christmas gift and unfortunately, this product is quite a disappointment. The actual rubber ring on the plunger doesn't form a tight enough seal thus, there are coffee grounds/loose tea leaves contaminating the entire cup. It is completely unusable and will now sit on a shelf as the person for whom I purchased the gift feels guilty in throwing it out!