Anybody know what bag this is and what it’s temp rating is?

I inherited a North Face sleeping bag when my uncle passed away. I believe it is a -20 or -40 bag but can't find the model. Does anybody know what this is, have experience with it, etc… The top loft is ~5" after fluffing and letting it sit for an hour (no washing yet). It weighs ~4 lbs without either the stuff sack or storage bag.