The Summit Casaval Hybrid Midlayer Hoodie is an essential layer you can dial up or down depending on the temperature and conditions. Highly breathable Ventrix™ insulation technology features perforations in key zones that open with movement, allowing excess heat and perspiration to escape during high-output pursuits, while remaining closed in times of rest to retain warmth. There's a whole host of features, too, like the helmet-compatible hood, stretch-woven underarms for full arms-up mobility, and a water-resistant coating that protects against light moisture. Plus, no shoulder seams mean this midlayer jacket is comfortable when wearing a backpack.