G'day Tom, 

For consistency we go by Sea to Summits compressed size, which is measured by the standard test method for measuring the volume of sleeping bags (ATSM F1853-11).

I've just double checked the specs provided by the supplier, and it says that the Trek TkIII long it’s going to be 7.05L compressed. The dimensions of the bag compressed will probably depend on how much force you use to compress it, so it’s hard to give a black and white answer there unfortunately. 

G'day Robert, 

I've just had a chat to our warranties manager and they've said that we haven't had an issue with a damp smell for any of the Sea to Summit sleeping bags, so I'm not too sure how that could happen unless it somehow got wet in transit. 

Down will have a slight odour as it's a natural product, so firstly we would suggest airing out the bag in a well-ventilated area, and if you still feel that there is a damp odour - give us a call on 1300 914 007 and we'll look into it further for you Robert. 

G’day Stijn,

The Seat to Summit Trek TkIII is the warmest in their Trek range and it has a comfort rating of -5 degrees so it is designed for Autumn/Winter weather.

I would say that if you’re cold at home on a 15° night, then chances are you’d want a bag that was on the warmer side like the TkIII. If you’re a hot sleeper you might want to consider the TkII as that has a -1 ° rating.

As far as we know there aren’t any bags that are designed to be used in Summer and Winter, but in general it’s better to be a little too warm and unzip your bag, then be too cold and not be able to do anything about it when you’re out in the elements.

When we refer to space for a wider frame, we are really comparing it to the mummy shaped bags which are very restrictive. If you are not a particularly cold sleeper, then this bag will be suitable for you. It has suitable drawstrings in place so you can wrap yourself up in the bag and trap all the warm air, and it provides versatility in its temperature range across warm and cold temperatures. Furthermore, by adding a thermal liner you can make the bag even warmer for mid winter expeditions.

Hi Kim, this sleeping bag has a comfort rating of -5 and a lower limit of -11. Sorry for the confusion, I'll get the fixed in the product description.

The difference in packed size between the two will be negligible Hannah, and it really depends on how you look at the 200 g of extra weight. There is no point in getting a cooler bag and end up throwing 200+ grams of extra clothing in to compensate, you might as well get the benefit of lightweight down in the warmer option. I would recommend the Trek 3 for alpine use also. These have a relaxed shape and will not be as efficient as a mummy bag such as the Talus, so more down is better. This shape has its benefits in warmer climates though... there is always a trade off.