Ivan Suvorov, an Unangax/Aleut hunter, wearing a gut parka and carrying a large harpoon in the Aleutian Islands, Alaska, USA, 1909

For thousands of years, Alaska Natives have used mammal intestines from seal, sea lion, beluga whale, and bear to create lightweight, breathable, waterproof coats. These garments were worn while paddling kayaks and umiaks to protect from the cold water and rain. Panels of gut were held together with a special waterproof stitch, resulting in a completely waterproof, but also fully breathable, jacket.

https://www.anchoragemuseum.org/exhibits/arctic-remix/remix-objects/gut-skin-parka/

That hat looks EPIC

The hat goes super hard