Patagonia Men's R1 Air Zip Neck - Black SIZE:XL These properties mean the Proton

These properties mean the Proton works outstandingly well as a mid-layer beneath a shell

and clip fastening lid

with significantly lessened weight penalty

A nice final touch

Patagonia Men's R1 Air Zip Neck - Black SIZE:XL These properties mean the ProtonA finely tuned bit of technical fleece from Ventura's finest. Patagonia are the fleece pioneers so it's maybe no surprise they're still pushing this majestic synthetic fabric forward with designs like this. The R1 Air Zip Neck is a lightweight, performance oriented piece, designed to take on some serious alpinism, with a low profile design allowing it to fit under jackets and harnesses with ease. Constructed from a fully recycled polyester jacquard