The Garmin Instinct 2S Solar in Graphite is a compact 40mm rugged outdoor GPS watch built for hikers, runners and everyday adventurers who want near-limitless battery life without carrying a charger. Its Power Sapphire-style solar lens tops up the battery from ordinary daylight, pushing smartwatch-mode battery life from 21 days on battery alone to up to 51 days with solar charging, and GPS-mode battery from 22 hours up to 28 hours with solar assistance; in battery saver mode it can run for 50 days on battery alone or effectively unlimited with enough sun, and max battery GPS mode reaches 54 hours (114 hours with solar). The 40 x 40 x 13.3mm fibre-reinforced polymer case weighs 43g and uses a monochrome, sunlight-readable transflective MIP display (156 x 156px) rather than a power-hungry colour screen, which is exactly what makes these battery figures possible. It is water rated to 100m (10 ATM), suitable for swimming, uses 20mm QuickFit-compatible straps for easy band swaps, and supports multiple GNSS systems (GPS plus others) for reliable positioning in difficult terrain. This is a strong pick for anyone who prioritises weeks-long battery life and rugged durability over a bright AMOLED display — buyers who want a colour touchscreen should look at the Instinct 3 AMOLED or Venu ranges instead.