Aerus 55L by Bonfus

Ships in 1-2 business days | Based in Lombardia, Italy | Est. 2019

An ultralight pack design with a curved frame for airflow

The Aerus 55L is the ultimate ultralight pack for thru-hikers and backpackers offering exceptional ventilation and comfort. Its adjustable curved frame and tensioned mesh back panel create a breathable gap, reducing sweat on hot hikes and controlling moisture in cold weather to prevent chills and improve safety.

Crafted from ultralight, durable fabrics with taped seams, it’s built for long adventures. With spacious side pockets, spider buckle compression webbing, and an advanced frame-to-hipbelt weight transfer system, the Aerus 55L delivers versatile storage, ergonomic comfort, and trail-ready performance.

Features:

• Internal Frame - the curved, tensioned mesh back panel creates a breathable gap allowing airflow and reduced back contact. The strategically placed anchoring point minimizes horizontal bounce, and it follows the shoulders reducing pressure points and improving fit

• Padded Hip Belt - additional 8mm lumbar padding, 1.5" | 38mm wide webbing for a secure supportive fit

• The rigidity of the mesh panel can be adjusted for optimal comfort and fit at the point where it connects with the hip belt

• Optimal weight distribution with a hip belt that is connected to the frame's bottom end and load lifters on the top

• Shoulder straps contain 7/16" EVA foam lined with breathable 3D spacer mesh for all-day comfort with additional 3D mesh around the neck area for enhanced comfort

• A spacious front mesh pocket with a triangular tip provides extra capacity, secured with adjustable webbing to hold items like rolled mats

• Two large side pockets hold two water bottles or other essentials

• Roll-top closure and Y-strap with extra-long webbing for securing bulky gear

• Side compression webbings conveniently clip with spider buckles, allowing quick and secure attachment of items to the sides of the pack

• Ice axe loop

• Taped seams for increased water-resistance

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Specs

Volume: 55 liters

• Main body: 48L

• External pockets: 8L 

Number of external pockets: 3

Recommended load capacity: 40lb | 15kg

Sizing:

• Small: up to 18" torso | 45cm

• Hip Belt (small packs): 29.5"-39" hip | 75cm - 100cm

• Medium: up to 19.5″ torso | 50cm

• Large: up to 22″ torso | 56cm 

• Hip Belt (medium & large packs): fits 33"- 43" hip | 84cm - 110cm

*See our backpack sizing page to learn how to fit a backpack

Dimensions: 34.5"H (unrolled) x 38" circumference | 87cm x 96cm

Weight: 28oz | 795g (Medium*)

*small size reduces weight by 0.4oz | 10g, large size increases weight by 0.4oz | 10g

Materials:

• Body: Ultra200X™: 168gsm | 4.95oz/sqyd, woven 400D UHMWPE fibers with a recycled 0.75mil polyester film backing, 66% 200D UHMWPE and 34% recycled polyester

• Shoulder Straps, Side Pockets, Hipbelt: Stretch Mesh (nylon and spandex blend), 3D Spacer Mesh, EVA-foam

Made in Mexico

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Assembly Instructions:

Due to the shipping bulk created by the curved frame, the Aerus backpack may be delivered unassembled.

1- Insert the Aluminum Bars: Starting from the channel opening at the base of the pack, insert the bars with the curvature facing the back panel.
2- Position the Carbon Crossbars: Ensure the top two carbon crossbars are positioned above the aluminum bars. To insert the aluminum bars into the top reinforcement pocket, use your fingers to squeeze the pocket entrance and enlarge the opening. Extra pressure may be needed for new packs.
3- Secure the Velcro Band: Thread the Velcro band on each side of the frame through the aluminum loop located on the back side of the hip belt, and pull it tightly to create tension in the back mesh panel and enhance the frame’s arch.
4- Attach the Mesh Panel Toggles: Use your hand and slightly press down on the mesh panel with your body weight, then insert the toggles into the grosgrain loops on both sides.
5- Ready to Use: Your Aerus backpack is now fully assembled and ready for use!

Tip: You can also watch the video below to see how it’s done step by step.