One Jacket. Every Season. The AC400 Has You Covered!
Whether you’re grinding out a long run in the high country or smashing sprints on a frosty winter morning, the AC400 2-in-1 Windbreaker/Vest Combo is your all-conditions go-to!
Part of our UltraLite Running Series, this smart, season-proof design adapts to whatever the weather throws at you. Need warmth? Snap in the UL Running Puffer Vest. Heating up? Pack it into its own pocket bag and stash it in the windbreaker’s rear horizontal pocket — alongside your snacks and run essentials. Easy.
No more bulky cotton jumpers tied around your waist — just premium, ultra-lightweight nylon, an eco-friendly polyester fill (used in high-end snow gear), and months of thoughtful design poured into one sleek setup.
This isn’t just a jacket — it’s a game-changer for serious runners who demand function, flexibility, and style in every stride.
Note: Our windbreaker and vest designs are based on an athletic body shape. If you are leaning more towards a slightly looser fit or are between sizes, we suggest opting for one size bigger.
Please see sizing chart for guidelines.
8 reviews for 5am:RUN Womens AC400 2-in-1 Windbreaker/Vest
5.0
Based on 8 reviews
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1-5 of 8 reviews
Roxey
Verified owner
Great combo with warm vest and light jacket
Ben
Verified owner
Warm, light and a great fit
Kelli B.
Verified owner
Lightweight and extremely comfortable
Kelli B.
Verified owner
Carmel
Verified owner
I love this jacket. It’s so light but so snug. The vest is great and I have warn it underneath and over the top of the jacket when I have cooled off. So versatile.
Great combo with warm vest and light jacket
Warm, light and a great fit
Lightweight and extremely comfortable
I love this jacket. It’s so light but so snug. The vest is great and I have warn it underneath and over the top of the jacket when I have cooled off. So versatile.