Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Bitterly Disappointed

I've been a space pen user for >30 years. The standard model's cap fits nicely over the back of the barrel thereby elongating the pen into a "normal" pen size. The trekker will not do that. So try writing with it. Unless you have a hand the size of a 5-year old it's like writing with a stub, very uncomfortable, pretty darn useless unless you're just jotting down a word or two, maybe a phone number. You just can't use it as a pen. Bummer.