The Little Rock startup sells a $249.99 reusable sweat sensor for athletes who are tired of generic hydration advice. Its most revealing lesson is also its least glamorous: the hardware matters, but calibration, repetition and a stubborn respect for messy bodies matter more.
It builds watches for people who leave the pavement, cockpits for people who leave the ground, and sonar for people who leave the dock. In 2025 the unglamorous approach paid a record $7.25 billion.