The Garmin Fenix 6 Sapphire does everything you need it to—and then some. With its 47mm diameter, the Fenix 6 sits in the middle of the new Fenix lineup: The Garmin Fenix 6S Sapphire has the smallest 42 mm-diameter size, while the Garmin Fenix 6X Sapphire bumps up to a 51mm diameter. Garmin cut the lens from scratch-resistant sapphire crystal and encased it in a rugged stainless steel bezel or steel bezel coated in Diamond-Like Carbon. Packed inside the fiber-reinforced polymer case is a 1.3” color display and powerful battery. In its most efficient mode, Garmin says the Fenix 6 can get up to 48 days on a single charge. Garmin Fenix 6 Sapphire battery life: GPS mode: up to 36 hours GPS + music: up to 10 hours Max Battery GPS Mode: 72 hours Expedition GPS Activity: 28 days Battery Saver Watch Mode: 48 days A Fleet Feet tester reviewed the Garmin Fenix 6, and he squeezed nearly three weeks of regular training and use from a single charge. An interchangeable strap ties the watch to your wrist and lets you swap it in and out without any tools. Garmin also made the Fenix 6 watertight: It has a water rating of 10 ATM, which means it can withstand water pressures equivalent to 100 meters. Designers gave it a wrist-based heart rate monitor that lets you track your ticker so you can train in different effort zones, and there’s a Pulse Ox sensor that helps dial in altitude acclimation and improves sleep monitoring. Like other Garmin running watches, the Fenix 6 comes with GPS, GLONASS and Galileo tracking, and it gives you turn-by-turn navigation for when you’re running somewhere new. Complete with safety and incident detection features that can send your location to a list of emergency contacts, the Garmin Fenix 6 Sapphire has you covered from warmup to cool down.