Only down is able to give this superior warmth to weight and pack size required. The Crux Torpedo 500 uses the best down available, 850 fill power Polish goose down (its ethically sourced too) and has a comfort rating of 0C and lower limit of -6C (EN13537).
Whilst the waterproof 2 layer eVent outer isn't the lightest, most compact fabric going, the fact that it is durably waterproof means that both you and the down won't get wet on snowy and damp bivvies and that you won't need the extra weight and bulk of a bivvy bag for snow holing and cold weather camping. The breathability of the shell helps internal moisture management, meaning that your down won't freeze and get bulky and heavy. Each slant wall baffle not only reduces cold spots; they are made from mesh and are therefore very light. Each baffle is laminated directly to the eVent outer, unlike other waterproof sleeping bags where a waterproof outer is stitched over an existing bag, and thus the Torpedo range save loads of extra weight. The zip is a highly water resistant Riri Aquazip which uses diving suit technology to keep the zip as robust and watertight yet light and easy to use as possible.
The medium sized bag has 500g of down, an overall weight of 1130g and 188cm internal length.
All in all, this is a fantastic bag for serious Alpinists and mountaineers,but is also well suited to discerning backpackers and back country adventurers.
Waterproof sleeping bag, perfect for alpinism!
(0°C to -6°C)
Weight: 1190 g (Medium)
Fill: 500 g of EU 850+ Polish goose down (Medium)
Shell: 2-layer eVent with a 40 denier, 60 g/m² nylon face
Lining: 15 denier soft-touch nylon
Chest Baffles: Vertical V-tube
Other baffles: Slant box wall
Double zip baffle elimates drafts
Simple side wall elimates cold spots from ground
Adjustable neck baffle
46 individual baffles in total
Packed size: 21 x 30 cm
Roll-top stuff sac 75g
Large cotton storage bag 95g
Temperature rating: 0°C comfort, -6°C limit(EN13537)