Garmin announced that it is refreshing its line of smartwatches, including a new flagship Fenix 7X that gets up to 578 hours of battery life on a single charge thanks to the sun's power. There are also many other models, including a rugged option called the Epix.

There are three models of Fenix smartwatches. You can get the 42mm Fenix 7S, the 47mm Fenix 7, and the massive 51mm Fenix 7X with ultra-impressive battery life. The refreshed Epix smartwatch also features a more durable 1.3-inch always-on OLED display.

Battery life is definitely where the Garmin smartwatches stand out, as the Fenix 7 models come with optional solar charging. The petite Fenix 7S gets up to 90 hours and 162 hours on solar. The middle-sized Fenix 7 gets 136 hours, up to 289 hours with solar. Finally, the biggest Fenix 7X model gets an absurd 213 hours of battery or 578 hours with solar.

Obviously, your actual battery life may vary depending on how you use the watch, how much sun it's exposed to, and so on.

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For GPS tracking, the Fenix 7 smartwatches feature the L5 frequency range, which offers enhanced tracking compared to the other ranges.

Some other features of the Fenix 7 watches include a hands-free LED flashlight with red or white lights, a Real-Time Stamina tool, a new feature called Up Ahead, which tells you the location of aid stations, elevation climbs, water, and other points of interest on your hike.

For the Epix, you get the 1.3-inch always-on OLED display, up to 16 days battery life (six days with the always-on OLED enabled), and more. There's no solar charging with the Epix, so you need to decide whether the always-on screen is worth more than the solar charging feature.

The Fenix 7 watches can get pretty pricey depending on the size and materials. The smallest, cheapest model starts at $699.99. The Fenix 7X goes up as high as $999.99, so these aren't the smartwatches for budget-conscious buyers. The Epix is also expensive, starting at $899.99.

Related: What Is OLED?