Rucsac
40 litres minimum and 65 litres maximum, 50 litres ideal. Simple designs are best without excess side pockets, as these can be up to a kilogram lighter when empty. A plastic liner can sometimes be useful to keep things dry if it rains on the way to mountain huts, though plastic bags work just as well.
If buying new, be careful to get the right size for your back, as this makes a big difference in how comfortable it is to carry, and as always, go for the lightest model you can find.
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