Arc'teryx Aerios 18 Backpack, forage, brand new Arc'teryx Aerios 18 Backpack, Forage - Brand: Arc'teryx - Model: Aerios 18 - Size: 18L - Color: Forage - Model Number: X000009581 Product Description: *This item is also listed on other sites and may be removed without notice.* *We generally ship on the same day, but may be unavailable for extended periods. Please inquire in advance if you need expedited shipping.* *Please feel free to ask any questions or request additional photos.* *Category changes are possible within reason.* The Aerios 18 backpack features a patent-pending interchangeable harness system. Fine-tune the fit right before your hike and forget about your pack. It uses an extremely durable, ultralight grid pack material that repels light rain and is resistant to impacts, abrasions, and tears on the trail. Updates: Updated with FCO DWR treatment, reducing carbon emissions. Looking for a different size? Try the larger Aerios 35 backpack.