Instruct: Classify Amazon reviews into positive or negative sentiment
Query: The chest strap for this is very small and itchy.

I am a male around 5'10" around 300lbs, I have always had a stocky build. I wanted to use this product while I exercised to make sure my heart rate stays in the range I need it to. This chest strap is very small and very uncomfortable. The arc that is preformed on the watch would be better if it were spread out more.