Uh, ok, so a Left and a Right will zip together. But what does it mean that "...it will zip up with any other bag too"? Could one get a Left Mens Long and zip it to a Women's Long (which I assume is a Right zip)? How would that work with the different lengths? Or should one simply get a Left and Right Men's Long and let the lady have a little too much length when not zipped together? Inquiring minds.....

suprisevalley -- I measured about 16" from the bottom of the bag (Long) to the start of the zipper. You do end up having separate foot boxes--since the zipper ends at the hood technically you have separate headroom as well. As to temps when zipped together, this will be opinion, but zipping the bags together isn't something you do to be functional. It's a fun here and there feature for when you're feeling snuggly. Think of it as being in bed but instead of having the openings of the sheets on the sides of the bed, where you can pull them back if you're too warm, the opening is in the middle between you and your partner. It limits what you can do to regulate that heat and really given it's two mummy bags, when zipped together it's either lay there shoulder to shoulder, or spoon. (Back to back perhaps if you're fighting, but then you wouldn't probably zip together in the first place.) The wife and I have combined bag-forces a few times, but mostly keep our bags close, but separated. Long answer short: the only time you would zip two bags together for function over fun would be perhaps in a hypothermia skin-to-skin situation.

Andrew- How far down do the zippers go on these bags? i.e. when you zip your sleeping bags together do you have separate foot boxes? Also, how is the temperature with two people in a giant 20 degree bag? I feel like the combined body heat would make it much warmer and possibly too warm, have you had any problems with this? Thanks a lot for your help.

Well, I purchased two men's long, one left zip and one right zip. They zip together amazingly well and the two of us are toasty and happy. ---------------I have a mens long and my wife has a womens long, and even with a slight length difference we can zip them together fine.