G'day Tim,

The comfort rating when adding a sleeping bag liner would depend on the liner used. The Thermolite Reactor Compact adds up to 11°C warmth, the Thermolite Reactor Extreme adds up to 15°C and the Thermolite Reactor Fleece Liner adds the most warmth up to 18°C. You would add one of these amounts to the comfort rating of the Spark 3 for the approximate total rating. 

G'day Mike,

We'd recommend the Spark III.  Generally, you should look at a sleeping bag that has a comfort temp of around 5ºc lower than the lower temps you expect to be in, or possibly 10ºc lower in you're a cold sleeper.  Eg. I'm a cold sleeper, I need a -10ºc bag which I use for all trips, year round.
The Spark 3 also has a longer zip down the side, so there is the option of opening it us and using it like a quilt for the more warmer trips.
Might also be worth reading through the product reviews on the Spark III to gauge real life use and comfort temps.  Even though everyones bodies are different, theres some great feedback there.

It comes down to gender, Meaghan.

The Flame series are made with a women's shape in mind i.e wider hips and narrower shoulders, whereas the Spark are generic or unisex in shape. The Flame series also have a little extra down to make them warmer to make up for the fact that in general females sleep colder.

That being said, if the Spark feels more comfortable or suits your dimensions then that's a better choice.

I hope that helps.

G'day David,

The internal foot girth is 94cm, so width wise it will be a little less than half of that. Height wise the Spark SP3 is designed for max user height of 183cm, however, if you check out our video Ben has jumped in it and has a little bit of room to play with, he is 185cm, so I would say you'll be ok with the regular length.  

G'day Matthew,

The external shell of the Spark SP3 is a high-performance 10D nylon with no DWR. The down itself is RDS 850 Loft Premium Goose ULTRA-DRY Down™ so will repell external moisture and condensation

G'day Riley,

The Spark SP3 is referred to as an expedition mummy style bag. This will give you slightly more room than a full mummy style, but if you're not comfortable in a tight-fitting sleeping bag it might cause you some anxiety. You would likely be better with one of the Trek range, they have a little more space and a foot zipper to open out the bottom if you need.