"Never-want-to-miss-again" item! I love wearing the vest on my trail runs in the mountains, when the weather is unpredictable. Your core is protected and you can easily regulate the temperature with what you wear underneath. Super light, minimal pack size, so easy to fit in every trailrunning backpack.
Also great for cross country skiing or winter hiking, when you heat up easily and need some wind protection.
Pockets are big enough for the essentials like your phone, keys and a power bar, so you're good to go. No autumn season without the vest anymore!