Instruct: Classify Amazon reviews into positive or negative sentiment
Query: worthless thermos

i've been well satisfied with thermos products for over fifty years. i was skeptical when nissan bought thermos a while back, but nissan improved the line substantially. i bought the wide mouth thermos because the wide mouth would allow me to use the bottle for a variety of liquids since it would be far easier to clean: most of my hand fit inside.this product has a top that renders it almost useless: it is very difficult to line the threads up to screw it on correctly; this product lacks an interior stopper so that the exterior cap could be used as a cup. a thermos without a stopper decreases insulation.