The volume size 37L is ideal for weekend, section, or thru hikes where resupply points are less frequent, or for equipment flexibility. Straight zipper makes it easy to access the inside When the extra volume is not in use, the Fastzip 37L top can roll down enough to make the overall size of the pack similar to 38L, but that additional space can come in pretty handy when you need it. Features : 37L Cappacity Rolltop System Vertical Zipper Front Pocket Hipblet Pocket Shoulder Pocket Load Lifter System Bottom Pocket Trekking Pole Loops Materials Spesification : 420D Nylon Composite Fabrics 10mm Padfoam 3D Spacer Mesh Nylon Webbing Acetal Buckle Techical Spesification : Dimension : 38 x 23 x 79 Torso : 48cm S/M Asian Torso Weight : -/+ 550gr Max Load : 12kgs