The Mountain Equipment Xero 550 has a slightly lower temperature rating than some bags here, being comfortable down to -8 deg C for an average man. It is also a good size, with 79cm of shoulder width and 213cm of length, but the result is that it’s slightly heavier than some bags at 1041g without the stuffsack. Inside you’re getting top-quality insulation comprising of 93 per cent down and just 7 per cent feather. This down is ethically sourced and its production audited through Mountain Equipment’s Down Codex programme. For maximum efficiency the outer fabric includes stretch fibres so the bag hugs the body a little closer to prevent cold spots. The down is captured in slant wall baffles to minimise cold spots. The side zip doesn’t extend to the foot, but instead stops at the calf area, which I like as it allows my feet to stay cosy while my legs are vented. There’s an excellent baffle behind this zip plus an anti-snag strip, and together these worked well without the zip jamming. You get a big shoulder baffle and a very well-profiled hood, and the hood and shoulder baffle drawcords both work very smoothly. There’s no added water resistance to the down or the shell, though, so it’s important to protect the Mountain Equipment Xero 550 from tent condensation. Also, the stuffsack doesn’t have any means of compressing the pack size.
Weight (with stuffsack) 1041g (1098g)
Length x shoulder width 213x79cm
Packed size 19x34cm
Outer fabric Helium 30
Inner fabric Supersoft 20
Insulation 93% down, 850 fill power
Construction slanted box wall
Comfort -3 deg C
Lower comfort limit -8 deg C
The Mountain Equipment Xero 550 is a very good year-round bag with an excellent set of well-designed features; but it lacks benefits such as more water resistance and a compression stuffsack.
Review by Graham Thompson
Published in Trail magazine June 2014