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Mont Highland Hydronaute XT -10ºC

photo: Mont Highland Hydronaute XT -10ºC 3-season down sleeping bag


Price MSRP: $718.14
Weight 1060g
Down Fill Weight 600g
Down 825–850 Loft 95/5 Premium White Down with DWR Loft treatment Unsure about down?
Shell Fabric Hydronaute XT
Temperature Rating -4ºC to -10ºC
Maximum User Height 185cm
Maximum Shoulder Circumference 160cm
Intended Use Alpine


1 review
5-star:   0
4-star:   1
3-star:   0
2-star:   0
1-star:   0

The Mont Highland is a lightweight alpine bag for cold weather. This bag has been excellent for the wet-cold nights in the Tasmanian mountains and the dry-freezing nights in the Himalaya. It is well designed and great for those trying to cut weight without skimping on warmth.


  • Waterproof exterior
  • Breathes well and doesn't gather condensation
  • Warm
  • Toaster pocket is a nice touch
  • Dual hood drawstrings (different materials for finding by touch)
  • Lightweight for warmth


  • Bag is quite long
  • A touch roomy inside and takes a bit to warm up
  • Could be marginally lighter if a tighter mummy fit

I have found that this bag lacks any sort of draft or cold-spot. Mont really went overboard with the double draft tube and lack of foot zip. I only bust this bag out when it's going to reach freezing or below. The "toaster pocket" is a little velcro pocket in the foot box designed to fit a chemical hand warmer, and it works surprisingly well for warming the bag.

I have used this when camping at the Walls of Jerusalem in Tasmania in winter and put the hand warmer in the toaster pocket 30 minutes before I went to bed. It made for a toasty sleeping bag when it came time to go to sleep. The above photo is of me in a teahouse in Gorak Shep, Nepal, which is around 5100m in elevation and very cold at night. The bag takes a bit to warm up, due to its size and I found getting in with an extra layer, and taking it off when I was warm, helped with the transition from freezing air to cozy sleeping bag.

Fit, Features, and Size

The standard bag comes with a left hand zip and a full-length zipper that does not include the foot box. This way, there is no potential heat-loss through the foot box zipper. The bag is more roomy than others I have tried in the temperature and weight range. It's quite long and I am able to stuff the day's clothes in the bottom with footwear if needed (and not feel cramped). The hood is large and lofty. On the right hand side, there are two cords attached to each other that are used to tighten the hood and draft collar.  One cord is flat and one is round. This way you can adjust the one you want by touch alone.

For reference, I am 175cm/5'9" and 70kg/155lbs.

Materials and Moisture

The external bag is made with Hydronaut XT and is said to be waterproof, but I have not had to test HOW waterproof it is. Although, at a teahouse in Nepal a guest in the floor above me spilled a water bladder and I had a constant drip through the ceiling for a couple hours that didn't penetrate the bag.

I can attest to how well the bag wicks moisture. Tasmania can be quite wet in the winter, and sleeping in huts in the rainforest can lead to damp gear from ambient moisture. I have woken completely dry in the morning while a friend with a S2S Spark IV woke up damp from condensation. Also, in winter, when laying outside, I have awoken to find a layer of frost on by bag while being completely dry inside.

I have a number of Mont items and they are all top-notch quality. This is no different. The stitching is excellent and I have found very little down escaping the bag even after living out of it for five weeks straight. I have only been using this bag for one winter season and am now using my summer bag. If anything changes with this review I will update it.

Packability and Weight

I usually stuff my sleeping bag into the bottom of my pack-liner and pack everything on top of it. When I tested out the included compression sack, I found the bag would compress to about the size of a Naglene and a half. With 600g of DWR 800+loft down, it lofts beautifully when uncompressed.The bag weighs in at 1058g/37.3oz and is definitely worth its weight. I consider this light for the performance that I have seen from it.

Photo 2: Mont Highland XT with a S2S Silk Liner


I have used this product in the Tasmanian alpine during winter with temps down to -3c, as my work bag during winter on the Tasman Peninsula, and in the Himalayas in October at altitudes up to and beyond 5000m. This is my winter and cold climate bag, and I use the Mont Helium 300 as my three-season bag.

Source: bought via a "pro deal"
Price Paid: $475AUD (w/40% prodeal)


Nice review of your bag, Josh! Sounds like it's been on some great trips with you.

2 years ago

:D It sure has!

2 years ago

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