The MT500 AIR 55+10L is the largest pack in this women's lineup, and at 1,725 g it works out to 26.5 g per liter — a better ratio than either MT100 version despite being a bigger pack with an expansion collar (55L base plus 10L extension).
The AIR ventilated back panel relies, like the other models, on aluminum stays and tensioned mesh, while the 210D RipStop polyamide fabric is more tear-resistant than the thinner polyester used on the smaller packs, which makes sense for a volume aimed at longer trips with heavier loads. Two ice axe loops suggest this pack is meant for rougher mountain terrain, not just marked trails.
An integrated rain cover, hydration bladder compatibility, and a padded hip belt with pockets round out the standard Forclaz feature set, and the 10-year warranty applies here too. For treks that require carrying more gear over more days, this model offers a reasonable balance of volume and weight.