Whoop 4.0 is smaller, more powerful, and now works with a new line of apparel.
It is the company's first tracker with an EDA sensor for monitoring the body's response to stress.
Fitness tracking without all the distractions.
Four day battery life, fitness and sleep tracking, and a price point under $200.
This fitness band goes step further than the usual heart rate monitor.
The hugely popular activity tracker gets a sequel.