This is the warmest puffer jacket Sitka makes, built to be light and packable for the ounce-counting big-game hunter on their coldest hunts. Made with 800-fill PrimaLoft Gold down blend, the insulation resists clumping in wet conditions maintaining warmth when you need it most. A 27D ripstop face fabric makes the HyperDown Jacket as tough as the conditions it is worn in, and it is cut to fit over your other layers and optics harness for rapid deployment.