Think of the Southwest as our "close quarters" trail pack. When the route is thick with vegetation that fails to recognize personal space, requires the occasional up and over immovable objects, and calls for "suck in your gut and shimmy through" type moves, the Southwest&&';;s solid and durable DyneemaA(R) Hardline panel pockets will keep those contents you want to easily grab throughout the day protected and free from any unwanted snags. The superlight and time-tested main compartment of the Southwest is constructed with 100% waterproof DyneemaA(R) Composite Fabrics, so regardless of where your chosen trail is heading, and despite what Mother Nature feels like sharing each day, your chances of unpacking dry gear at camp are better than great. The 3400 volume size (55L) is ideal for weekend, section, or thru hikes where resupply points are less frequent, or for equipment flexibility. When the extra volume is not in use, the 3400&&';;s top can roll down enough to make the overall size of the pack similar to the 2400, but that additional space can come in pretty handy when you need it. SPECS & DIMENSIONS MaterialsDCH50 & DCH150 Internal Volume55L External Volume9.8L White Pack1.98 lbs Black Pack2.18 lbs Load CapacityUp to 40 lbs SizeUp to 40 lbs Back Width10.5" | 26.7cm Height (Fully Unrolled)34" | 86.4cm Top Circumference40" | 101.6cm Bottom Circumference33.5" | 85.1cm