G'day Juan,

We've touched on this in another question, but ultimately no.
The zip on the side is only 7/8ths long, so you cannot fully unzip this one to lay flat.
You could open the side zip fully and use most of it as a doona, but you'd have a pocket at the base for your feet to go.  
Similar to a hiking quilt!

G'day John,

Yes, as far as we can tell you can zip two bags together if you get a left zipper and a right zipper. One thing to note is the zipper is only 7/8ths of the bag length, so you won't be able to individually adjust your foot temperature like some other down bags.

Both are great bags, Rachel, there is no standout reason why you should buy one over the other but I'll try and help as best I can.

First thing to note is that Sea To Summit has a strong reputation in technical sleep systems and the Trek has been part of their range since the start with a number of improvements made along the way. Black Wolf is a little newer to the lightweight down bag range, and while I've no doubt they will perform, you don't see as many of them in the field as the Sea To Summit range in general.

Other things to point out are that the Trek probably has more wiggle room and comes in a little lighter, it also has vertical baffles over the torso which will increase efficiency. The Black Wolf Hiker bag has more of a mummy shape, heavier denier fabrics and weights a bit more, it also caters for a taller sleeper.

I would personally choose based on weight and/or price if I couldn't split the difference otherwise.

G'day Nina,

The Hiker bag comes with the lightweight compression sack plus a mesh storage sack for longer-term storage.

G'day Lana,

We'd suggest doubling checking with your tour group but we think the temperature rating of the Hiker 300 should suit. Kokoda in August is pretty hot and humid so you might find a synthetic bag will suit your trip a little better. Maybe give us a call and we can chat through a few options.

G'day Bradd,

I've done a little research around temperatures that you're likely to encounter in December and it looks like the average overnight temp on the Overland sits at around the 5° mark. Obviously, being an average, there's a chance that you'll have nights that are both warmer and colder than the 5° mark. The Black Wolf Hiker 300 Sleeping Bag has a comfort temperature rating of 4°, so you'd most likely be pretty comfortable but if it gets really cold then you might have a few restless nights. The Equinox 300 is a warmer sleeping bag, with a comfort temperature rating of 0° but it's nearly twice the size and weight of the Hiker, so it'll take up a lot more room in your pack. It might be worth making the decision between whether the warmth or the size is a more important factor for you.