Amazfit's Helio Strap has been around since June this year and the screenless fitness-tracking wristband has quickly gained traction among sports enthusiasts worldwide. However, the Helio Strap only supported 27 sports at launch, compared to a whooping 177 featured on some of Amazfit's smartwatches (like the T-Rex 3 we reviewed). Previously, tennis training with the Helio Strap involved a hit-or-miss approximation of the activity. Unlike many other wearables for fitness enthusiasts, the Helio Strap does not require a subscription. You can buy the Amazfit Helio Strap fitness-tracker for a one-time payment of $99 on Amazon.