I love this pack. I struggled at first when look at the osprey line because they range from 10 to 30 liters in size. I went with the manta 20 becuase I wanted a day pack that could work for short mountainbiking trips to all day rides. This pack is perfect for MTB. Stays super tight with hip belt straps, chest straps, and shoulder straps. The bladder has a rigid back so it doesn't slosh around when you are riding some bumpy singletrack. Perfect for an extra layer, food, your tools, extra tube, and your water. I also love this pack for day hiking. It has all the features of a full sized pack. Hip belt with pocket, trail pole strap, hydration bladder, included rain cover, etc. I bought one for my wife and she loves it. Certainly a little heavy but you won't find another 20 liter pack with all of these features. Get it!