My sleeping system for the Iditarod Trail Invitational is in a whole new league to what I've tried before. A Hispar 800 sleeping bag tailored to my height and shape, with a short zip to minimise heat loss. The down is the best quality I have come across, and the standards in making the bag are phenomenal. My favourite piece is the bespoke, waterproof, synthetic-filled bivi bag. I've had issues in the past with the amount down compresses, so always wanted a synthetic base to a bag - this is a great way of doing it. And...if the temperature drops to -50C or colder, I'll pull on some down clothing too, and then be good for about -60C! Huge thanks to the superb PHDesigns.