What's the secret to the jacket's minimalist weight? It took Mountain Hardwear two years to design and perfect the ultra-light Whisperer 7D x 10D ripstop nylon fabric. In fact, there's only one mill in the entire world that can weave this ultra-fine fabric. An incredibly laborious process, it takes approximately ten-times longer to weave the Whisperer's fabric, compared to that of larger yarn size. The final product is a super-light fabric that's woven very tight, making it virtually down proof to prevent clusters from escaping through tiny gaps. Keeping you nice and toasty, the jacket's 800-fill Q.Shield Down has an ultra-high loft rating for tons of warmth without the heft usually associated with synthetic insulation. Knowing that down's insulating properties go out the window once it gets wet, Mountain Hardwear developed Q.Shield Down. Treated with a water-resistant coating, Q.Shield Down retains its heat-trapping properties in wet, soggy conditions, making it a great choice for nasty weather.