Engineered for summit pushes on the world’s highest and harshest mountains, the Mont Expedition 8000 XT Sleeping Bag is purpose-built for elite alpinists and polar explorers who demand absolute reliability in the coldest environments on earth. Designed with a generous “expedition fit,” they accommodate layered down clothing for high-altitude bivouacs and extended time in extreme conditions, with sizes available in Small/Medium and Medium/Large.

Rated to an uncompromising -40°C, these bags are crafted to deliver life-preserving warmth when conditions turn truly hostile. Every detail is optimised for performance in severe cold: Hydronaute XT laminated membrane fabric shields against spindrift and external moisture while efficiently venting internal vapour; vertical chest baffles stabilise insulation to eliminate cold spots; and a close-fitting, down-filled hood with Hydronaute XT lining guards your head and keeps critical insulation dry.

A spacious foot-box design with Hydronaute XT lining ensures your down stays protected from snow-covered socks or booties, while Mont’s innovative Cordless Collar System wraps the shoulders in exceptional warmth without the discomfort of traditional drawcords. Interlocking down-filled draught tubes run the length of the zip, sealing out the cold and locking in heat when the temperature plummets.

When you’re pushing toward the summit or riding out a storm at altitude, the Expedition 8000 XT is built to keep you warm, dry and alive.

Comfort Temperature Rating for warm sleepers: -40°C, cold sleepers: -30°C. These ratings suggest the average user will be comfortable at or around those temperatures. These temperature ratings assume you're using an appropriately insulated sleeping mat, you are well hydrated, well fed and dry.

Standout Features

HYDRONAUTE XT SHELL: Comfort in the Extreme: Using advanced monolithic PU membrane technology, Hydronaute XT fabric is completely waterproof, totally windproof & highly breathable. Guaranteed to maintain greater warmth & comfort than coated fabrics, Hydronaute XT is the best protection for down sleeping bags & clothing in cold to extreme conditions. Waterproof to 20,000mm, highly breathable 48,000g/m2/24hrs: If not removed promptly, water vapour from your body will gather on the down & reduce its ability to trap warmth. Hydronaute XT fabric expels 20L of water vapour per square metre per 24 hours for drier down, greater loft & maximum warmth. Warmth Sealed In: With a 100% windproof rating, even Arctic blasts will not penetrate Hydronaute XT fabric, keeping warm air trapped inside.

RADIAL ARC BAFFLE: The Radial Arc Baffle System is a significant design innovation that improves the thermal efficiency of a Mont sleeping bag. Radial Arc baffles curve naturally around your body rather than compressing the down around your body.
When a down baffle (chamber) is bent, ripples in the fabric occur, which will create cold spots and compress down. The radial Arc Baffle System reduces distortion and increases warmth and loft

CORDLESS COLLAR SYSTEM: A cordless Collar System provides superior insulation around your shoulders and neck without the need for uncomfortable and fiddly draw cords. The Cordless Collar can be wrapped snugly around your neck and shoulders, or in warmer conditions, can be secured inside the sleeping bag to increase ventilation. The Cordless Collar is a unique Mont design and can be found on Brindabella, Spindrift and Expedition 8000 sleeping bags.

TUCK STITCHING: Tuck stitching is a construction method that conceals the stitch inside the sleeping bag, thereby protecting it from abrasion and snagging. This is in comparison to top-stitched seams, where each stitch is exposed, which is commonly found in other sleeping bag brands. Tuck-stitched seams are also more water-resistant than top-stitched seams, again because the seam is concealed internally. Tuck stitching attaches the lock-knit baffle to a small fold in the shell material.

TOASTER POCKET: is for slow-release, air-activated heat packs: your toes and feet will never be cold again.

More Help? For further assistance on choosing your down sleeping bag, we have an article explaining fill power, the pros and cons of down over synthetic insulation and more info on caring for your bag available to view here: A Guide to Down Sleeping Bags.

Features

Down distribution: 55% canopy 45% base
Large boxfoot section accommodates the wearing of inner boots or down booties
Cross block baffles on torso prevent down shift between canopy & base
Radial Arc Baffle System on horizontal baffles maximises baffle loft height & warmth
Differential cut reduces compression & cold spots
Box walled chambers for warmth
Twin interlocking down-filled draught tubes along zip retain heat
Durable laminated Nylon anti-snag shield along zip
Contoured hood with down-filled muff
Unique Cordless Collar System wraps efficiently around shoulders without the need for fiddly and uncomfortable drawcords
Drawcords across chest and at top of hood
Recessed drawcords provide comfortable, warmth retaining closures
Tuck stitched seams: a construction method that conceals the stitch inside the sleeping bag thereby protecting it from abrasion and snagging. Tuck stitched seams are also more water resistant than top-stitched seams
Sewn with hydrophobic Epic thread to prevent moisture from wicking along seams and inside the shell
Toaster Pocket in boxfoot for air-activated heat pack
Full length YKK side zip with dual sliders
YKK Anti-snag slider cover
Includes siliconised-Nylon mechanical advantage compression stuff sack & 50L / 3,051cu.in polyester storage sack with printed care & washing instructions

Specification

Intended use: Expedition, Alpine
Season Rating: 4-Season
Maximum User Height: S/M: 185cm / M/L: 200cm
Cold Sleeper Comfort Temp: -30°C
Warm Sleeper Comfort Temp: -40°C
Down treatment: Water-resistant DWR Loft treatment
Waterhead: 20,000mm +
Moisture Vapour Transmission Rate (Breathability): 48,000g/m ²/24hrs
Max Shoulder Circumference: Women's: 155cm / Regular: 160cm / Long: 170cm
Insulated collar: Yes
Shell Fabric: Japanese-made Hydronaute 2-layer XT™ 12D PU laminated
Lining: Ultralight silk-touch 15D downproof Nylon
Filling: Premium white duck down
Fill power: 900+
Weight: Women's: 1565g / Regular: 11630g / Long: 1785g
Fill Weight: Women's: 1000g / Regular: 1000g / Long: 1100g
Compression Size: 23x30cm(women's) / 23x30cm(standard) / 23x30cm(Long)
Zip: Women's: Right / Standard/Long: Left
Zip Configuration: Side & Foot zips. YKK brand zips, dual sliders on side zip
Colour: Turmeric/Fiesta Red/Black
Cut: Mummy

-30°C to -40°C

MONT Expedition XT 8000 Sleeping Bag -40°C