Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Sony Sports Radio Walkman

After a great deal of searching for a wireless AM/FM headset to wear at the gym, I found this to be the best unit available. I would have appreciated knowing that it is quite dated, as the promotional materials enclosed within the packaging had an expiration date of 5 years ago, but apparently nothing better has been developed by Sony since then. The stiff plastic ear grips that hold the headphones in position are not entirely comfortable if you're sweating through several hours of aerobic/cardio work, but they do keep the unit in place.