They are the old Royal Marine issue Arctic bags. They are like an updated version of the old 58 pattern feather bag. They have more filling and an external zip baffle, which easily distinguishes it from the standard 58. My brother was in the marines and did a 3 month stint in Norway every year. He says they were great bags and warm enough for the conditions. As with any Army surplus bags though...condition can vary. The bag could be 20 - 40 years old, may have been left rolled up on a shelf for years, may have been heavily laundered or dry cleaned, and may have lost much of the filling. Then again it could be an absolute belter of a bag. If they get them bag in stock I'd want to talk to them on the phone before buying. I'd apply all the above to a 58 pattern too. A good one is a great bag but a lot are way past there best by now.
I recently slept in the current issue synthetic bag and I was cold at 0 degrees. The bag looks like new but who knows how often it's been in a washing machine. It's past it's best as a winter bag though.
