Grayson Schaffer of Outside magazine is currently stationed at Mount Everest's Base Camp, with the assignment of covering climbers attempting to scale the summit 50 years on from the first American-led ascent. A mission such as this presents unique photographic challenges for a magazine used to glossy reproductions, and Schaffer has shared some information about how he's able to reproduce studio lighting above 17,500 feet. Aside from some umbrellas and a ring flash, the key piece of gear is apparently the Pro-B3 1200w/s AirS battery pack from Profoto, which Schaffer rates for its ability to "deliver consistent flashes even in subzero temperatures."