Rugged Outdoor Smartwatch

The manufacture and production of watches are based on a simple and witty invention, which is the　spring . It can tighten and store energy, and slowly release energy to push the running device and pointer in the watch to achieve the function of displaying time. This spring device in the watch is called the main spring.https://kospet.com/products/kospet-tank-t1-smartwatch.
Nailed 12 MIL-STD Military Tests
TANK TI leverages our most advanced technology with which it has nailed up to a dozen MIL-STD Military Tests.
Introducing *TM & IP69K Waterproof
Thanks to its elaborate water-resistant design, TANK T1 has you covered both for water and underwater sports daily.

https://kospet.com/products/kospet-tank-t1-smartwatch.