G'day Jakcob,

The TK1 is a previous season model, which ranges from 750-920g depending on the size.

The new season Trek -1 weighs 1.1kg, so perhaps other sites have the specification information confused between these to sleeping bags.

G'day Alisha, 

Any of the Mummy shaped liners would be the best fit, depending on how much warmth you want to add you could use something like the Sea to Summit Thermolite Reactor Extreme Liner.

G'day Sam,

The user height of this bag is 183cm, and you're under that - so no issues with the regular.
If you want more info, check out the 4:42 mark in our product video - Bens in the bag and he's 185cm.
Hope the helps.

G'day Mark,

No, they're not unfortunately, the zip coupling system only works between S2S unisex and womens specific bags.  Eg, the Trek zips to the Journey series.
This is due to the zip orientations being different on each bag.  The unisex bags have a left oriented zip, the womens specific have a right oriented zip.

G'day Joel,

The Treeline is Sea to Summits entrance level down sleeping bag. It just has a side zipper, RDS 600 Down, and a standard storage sack. The Trek TK1 has a side and foot zipper, so you can open it out as a quilt. They have RDS 650 Loft ULTRA-DRY Down™, and a compression sack. Overall both options are good, with the Trek Tk1 having a slightly higher comfort rating, and lower weight.

G'day Tim,

The Trek TK1 Sleeping Bag can't be zipped to another Trek sleeping bag but can be zipped to any of the Sea to Summit Women's bags that are zip coupling compatible. The Journey Jo1 has a right side zipper is considered the counterpart for the Trek TK1 and Tk2, which have left side zippers.

G'day Amanda,

Yep! The Trek Tk1 foot zip opens all the way around so you can open the bag up completely, like a quilt cover. Check out the video on the product page for clarification on the features.