Rucksacks and associated products have been divided by litreage. This means that super lightweight fell running sacks will appear in the same category as day walking sacks and so on, so please use the activity filters to narrow down your choice.
When it comes to fit it is important to select the correct backlength if a choice is available and also try the sack on with a suitable load in it. With large sacks in particular we suggest slackening off the tension adjusters on the shoulder straps and waistbelt and slackening off the waistbelt. Now put the loaded sack on, tighten up the waistbelt and lean forward at 90º. Now tighten the waistbelt further and straighten up - this places the load where it should be, on your hips. Then tighten up the shoulder straps and fasten the chest strap and finally adjust the tension straps. The top tension straps should slope downwards towards you at about 25º - on some bigger straps there is a buckle adjuster which can alter this angle. If you don't find the sack comfortable at this point, bearing in mind that it is carrying a heavy load, then it probably never will be and it's time to try something else.