Get an uninterrupted picture of your daily health and nightly sleep with up to 12 days of battery life in smartwatch mode and up to 26 hours in gps mode. With its sleek design and 1. 4 oz weight, you’ll almost forget you’re wearing forerunner 255s — even when you’re asleep. Featuring easy-to-use buttons and a silicone band, this watch is ready to wear — and tear — with durable corning® gorilla® glass 3.