Sleeping in cold and wet conditions will keep you from reaching your REM cycle and leave you groggy the next morning. The Zissou 30 is stuffed with 600-fill DriDown. Each feather is treated with a hydrophobic solution that makes it highly water resistant. Essentially, it's waterproof down. SD claims DriDown stays dry seven times longer, retains 34 percent more loft, and dries 33 percent faster than traditional down. With a temperature rating of 30 degrees F, the Zissou will keep you dry, toasty, and dreaming sweetly even on the coldest spring nights.