It depends on how you keep warm and how much you carry. Alpine is the most durable, uninsulated shell for layering: wear it over a base layer and add a fleece when it gets cold. Delta INS has insulation built in for cold days, winter walks, and travel. Aero is the lightest of the three at 300 g, and it packs into its own pocket for days when rain might come. Still not sure? The Product Finder matches you to a jacket in six questions.

Every product page shows the model's height and the size they wear, so you can compare against your own height. All our jackets are a regular fit with room to layer underneath. If it doesn't feel right, you have 21 days to return or exchange it in the EU. Or try it on first in our Amsterdam store at Bilderdijkstraat 136H.

Our shells use Barrier CT, a waterproof-breathable fabric we develop ourselves with specialist suppliers. We have it tested by an independent lab for waterproofing, breathability, and abrasion, and we publish the full results so you can check them yourself. 

We develop our own fabric technology and sell mainly directly to you, without paying an external membrane licence fee. This helps us keep our prices accessible while investing in materials, product development, and independent testing.

To shape how our jackets protect, breathe, and feel. We develop our fabrics to our own specifications and have their performance independently tested. Field testing shows how our products work in real conditions and helps us refine them further. That is the work behind Cortazu Technology Lab™.