Osprey Sirrus Backpacks

Consider your main activity:

• Hiking: Compatible with hydration reservoirs; some have straps or loops to attach trekking poles or other gear.
• Running: Designed to limit bounce; compatible with water bottles or hydration reservoirs.
• Climbing: Slim profile with abrasion-resistant reinforcements.
• Traveling: Has compartments for easy organization; many meet carry-on size requirements.

How much gear will you carry?

• 20L or less: Ideal for short runs, day hikes or quick outings.
• 21–35L: The sweet spot for hiking and travel.
• 36–50L: Best for extended trips or adventures requiring more gear or clothing.

Find the right fit:

• Daypacks are available in a range of sizes.

• Check your torso length and waist against the brand's size chart for the best fit.
• Many packs feature adjustable torso lengths to fine-tune your fit.

Backpack capacity

Backpacking packs can be 30 to 70-plus liters. To choose the right capacity, consider trip duration and the gear you’ll bring.

Backpack features
Think about the frame type, location of important pockets, padding and ventilation, among other things.

Backpack fit
Your pack should be sized for your torso length (not overall height) and hip circumference. You can try on packs at your local REI store.