This system is very similar to the one already used successfully on Broad Peak (see Case Study), but it advises a much warmer sleeping bag. In theory a Hispar 400 would do (the 400 has a similar rating to the Hispar Overbag used on Broad Peak), but the Hispar 600 only weighs a little over 200g (7.1oz) more and gives a greatly increased margin for mishap or bad weather.
As climbing kit, the Xero suit has summited on Everest before. It also doubles as the night-time booster which shifts the performance figure for the Hispar 600 from -21°C (-5.8°F) up to -47°C. The Hispar bag should be enough for lower camps by itself, but combined with the Xero gear it will provide enough warmth for comfort and safety at Top Camp on any route on the mountain.
: The Hispar 600K Down Sleeping Bag (Wide)
is available in the K Series. The exceptional loft of 1000 down reduces the weight to just 982g (34.6oz), creating a unique sleeping bag that still fulfils its -21°C rating at under a kilo pack weight.