Geoffrey L.wrote a review of Osprey Packs Insulated Delivery System on January 26, 2013
Familiarity: I've used it several times
I used this for three days of snowboarding in Utah recently. It was perfect the first day when the temperatures where in the high 20's. However, it was low single digits after that and the line & valve were frozen solid fairly quickly. Like the other reviewer said, it is great for keeping the valve clean as well. I would say it is worthwhile if the temperatures are not too low.