The new Garmin Fenix 6S Sapphire is a multisport GPS watch that packs tons of power into a smaller package. The “S” in “6S” is the smallest of the three versions of the new Fenix. The 6S’s diameter measures 42mm, which is best for runners with smaller frames. For larger wrists, the Garmin Fenix 6 Sapphire bumps up to 47mm, and the Garmin Fenix 6X Sapphire has a 51mm diameter. Like other Garmin running watches, the top-of-the-line Fenix 6S features GPS (and GLONASS and Galileo) tracking and music-streaming services through apps like Spotify. Designers also gave it a wrist-based heart rate monitor and Pulse Ox sensors to give you new insights into your training. Engineers set a 1.2” display into a rugged stainless steel or Diamond-Like Carbon-coated steel bezel and covered it with a lens cut from scratch-resistant sapphire crystal. The whole package has a waterproof rating of 10 ATM, which means it can stand up to water pressure equivalent to a depth of 100 meters (although it's not suitable for Scuba diving). Each watch comes with an interchangeable silicone strap that swaps in and out without the use of any tools. Underneath, the color display brings life to topographical maps and turn-by-turn navigation so you can always find your way, and new assistance and incident detection features can quickly send your location to a list of emergency contacts. Garmin also packed impressive battery life into the Fenix 6S. Garmin says the watch gets up to 25 hours in GPS mode and six hours in GPS with music. But changing the settings to Max Battery GPS Mode will net you up to 50 hours of battery life, Expedition GPS Activity mode goes for 20 days, and Battery Saver Watch Mode can last up to 34 days. In the Fleet Feet Garmin Fenix 6 review, a tester says he trained regularly for nearly three weeks on a single charge without changing any settings. He was confident the big battery would get you through any adventure you could think of. The Garmin Fenix 6S Sapphire gives you cutting edge performance and features for you smartest training cycle yet.