What Our Gearhead(R) Experts Are Saying:"I've taken the Sirrus 36 Hiking Backpack on everything from long day hikes to quick overnights, and the AirSpeed suspension is the real standout. The mesh trampoline backpanel keeps airflow moving even on steep, sweaty climbs, and the magnetic sternum strap closure is one of those small details that makes a big difference over a long day. The included raincover tucked into the bottom panel means one less thing to think about when the weather turns."A long day on trail demands a pack that keeps up without wearing you down, and the Sirrus 36L Backpack from Osprey was designed with exactly that in mind. Whether the plan is a big day hike with elevation to spare or a quick overnight with just enough gear, this pack brings structure, ventilation, and smart organization to every step of the approach. The AirSpeed suspension system tensions a mesh trampoline backpanel against a LightWire perimeter frame, creating a gap between your back and the pack that keeps air moving on warm climbs and steep switchbacks. A padded full-yoke harness with die-cut airflow channels and spacermesh contact surfaces keeps pressure distributed and irritation-free, while load lifters and the ErgoPull hipbelt work together to transfer weight efficiently, no matter how the miles add up. A top-loading main compartment, collapsible bottom-zip compartment, large front stash pocket, and generous zippered hipbelt pockets give every piece of gear its place, and a Stow-on-the-Go trekking pole attachment handles transitions without stopping. An integrated raincover stores in the base of the pack and deploys in seconds, so a weather change never turns into a scramble.