Having said that the Mountain Hardwear AMG 75 (which supersedes the South Col 70L) is a sack that is incredibly lightweight and packed with great features and is the most popular rucksack on the mountain.
[ ] 55-65 Litre rucksack. This needs to be comfortable when loaded and should have side compression straps rather than side pockets. NOTE – If you are particularly good at packing you may well be able to use your trekking rucksack if it is versatile enough (for instance the Crux AK47 (extendable) and the Crux AK57 all have a floating lid, side compression straps, elasticated webbing and are a reasonable volume and will do for the trek in AND on the mountain). Having said that the Mountain Hardwear AMG 75 (which supersedes the South Col 70L) is a sack that is incredibly lightweight and packed with great features and is the most popular rucksack on the mountain. But if you bring it then please, please don’t overfill it with extras