Definition: In this task, you're given reviews from Amazon's products. Your task is to generate the Summary of the review.
Input: I purchased this device back in June. I have been exercising regularly for a few years now and I decided to treat myself to this item as a birthday present: BIG MISTAKE. When I work out, I exercise vigorously. I go to the gym to get a good, intense workout in and usually come out sweating. I do both cardio and weights, but this device runs into the most problems when it comes to cardio. The heart rate tracker literally cannot read through my sweat. Yes you read that correctly - A FITNESS TRACKER CANNOT READ YOUR HEART RATE THROUGH SWEAT. How ironic. My heart rate will jump (during intense, steady-state cardio) from 165 to 110 to a blank screen (as you can see in the photo attached) to 150, then 98, etc. I contacted Fitbit customer service and was sent a replacement device. It also didn't work. Then, they sent me a SECOND replacement device. It also fails to accurately track my fitness stats. Given that this is the third device that has failed to record my stats, it clearly is their technology that is faulty. They refuse to reimburse me for their faulty product. If you actually care about exercising and want to do so with anything more than moderate intensity, don't even waste your money on this device. I'd recommend spending the extra $100-$300 on a Polar Watch or Apple Watch to get a product that will actually work for years at a time. I am so incredibly disappointed with this product and the Fitbit customer service team who, despite acknowledging the problem with their faulty technology, refuses to correct the situation with me.

DO NOT PURCHASE if you actually want to track fitness stats