Keystone Construction: Used in shipping sleeping bags Down, this construction allows positioning the opposite side face to face to eliminate possible ‘cold spots’, to keep a constant volume while keeping the down in place.
Two different outer fabrics: on top, a blue 22-denier ripstop nylon fabric, beneath a gray fabrics 30 denier Nylon Taffeta (see video). The blue part has a “ripstop” mesh (small squares) avoids a possible tear to expand, the gray area has a higher denier, more abrasion resistant;
The lining is gray goose down Hungary , 90/10, 650 cu.
The novelty is the addition of panels of insulating synthetic fibers sleeping bags (lawschoolsinusa, see diagram above). These anti-compression pads are designed to create a kind of insulating mat between the ground and the body. They are more resistant to compression than the natural down.
A first series of tests took place in early January on a mountainous route between 1300 and 2100m altitude, good weather with high thermal amplitudes. Relatively little wind, but few gusts of 40km / h at times, sometimes overcast sky morning disengaging to 9/10 hours. Bivouacs have followed ascents in snow 700 to 900 m elevation.
Site tests: Pre-Alps of Digne, Cousson summit, 1511m, North Slope. Chain of southwestern slope Estrop, 2050m.
bivouac conditions the hard way: small mattress moutain Lafuma 1.20m without outer bag nor survival blanket. The head of the compression bag filled with clothes down, feet on the backpack.
Temperatures wiped mini -6 ° max + 1
The 600g of 650+ duvet have pleasantly surprised me by their comfort and softness. Certainly this is not the impact of 800+ downs but the performance seem very correct and well in inflating the appointment.
Down is able to consider the 4 seasons favorable conditions for winter . That said the so-called comfort temperature which can claim this down seem a bit below that wants to announce the manufacturer.
The limit of -4 ° C will be hard to overcome without an excellent floor insulation and a consequent buildup. I would tend to indicate an operating range of + 8 / + 10 ° C (possible opening down the zip) -5 ° C mini with an effective floor insulation and adding a second layer to the -3 / -4 ° C. In addition it will be well covered, including the head with a cap.