VOLUME
55L (48L internal, 8L external)
PACK WEIGHT (Medium)
795g | 28oz
CARRY LOAD
HEIGHT (unrolled)
87cm | 34.5in
ULTRALIGHT WITHOUT COMPROMISE
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.
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.
THE RIGHT FEATURES
The Aerus 55L is designed for comfortable, efficient load carrying, featuring a curved, tensioned mesh back panel that creates a breathable airflow gap while conforming to the shoulders and lower back to reduce pressure and bounce. A pre-shaped 7075 aluminum frame with carbon fiber reinforcements stabilizes the load, prevents bulging, and transfers weight directly to the hips, with adjustable rigidity at the hipbelt for a dialed-in fit.
Plush, breathable shoulder straps and a supportive, wide hipbelt enhance all-day comfort, while generous storage—including large side pockets, a front mesh pocket, and a roll-top Y-strap—keeps gear accessible. Built from durable, lightweight Ultra fabrics with modular attachment options and an integrated ice axe loop, the Aerus 55L balances ventilation, stability, and versatility for demanding trips.
Plush, breathable shoulder straps and a supportive, wide hipbelt enhance all-day comfort, while generous storage—including large side pockets, a front mesh pocket, and a roll-top Y-strap—keeps gear accessible. Built from durable, lightweight Ultra fabrics with modular attachment options and an integrated ice axe loop, the Aerus 55L balances ventilation, stability, and versatility for demanding trips.
- A tensioned back panel creates a breathable gap, allowing superior airflow and reducing back contact. While a durable open mesh fabric ensures excellent ventilation.
- Made from reliable 7075 aluminum, the frame is pre-shaped to create the curved back profile that allows for the breathable gap between the pack and the tensioned mesh panel, enhancing airflow.
- The tensioned back panel and hipbelt are directly connected to the frame’s bottom end for optimal weight distribution.
- The shoulder straps are 11mm (7/16″) thick, comprising of EVA foam and lined with breathable 3D spacer mesh for all-day comfort.
- Ample storage includes large side pockets for bottles or essentials, a spacious front mesh pocket for extra gear, and a roll-top Y-strap system with long webbing to secure bulky items.
- The pack uses Ultra 200X for the main body, reinforced Ultra 400X on the bottom for abrasion resistance, and durable, flexible UltraGrid fabric on pockets, shoulder straps, and the hipbelt.
CUSTOMIZED MODULARITY
Optional
shoulder pouches
and
hipbelt pockets
(sold separately) integrate seamlessly via dedicated webbing loops on the shoulder straps and hipbelt, allowing you to customize your carry for quick-access essentials. The Aerus 55L is also fully compatible with accessories such as the
Large Packing Cube,
Food Bags,
and
Dry Bags,
creating a modular system that maximizes organization, efficiency, and adaptability on the trail.
PROUDLY MADE BY HAND
Bonfus develops, tests, and produces its gear in-house, maintaining full control over every stage of the process. This hands-on approach ensures that Bonfus stands behind every product it makes and delivers consistently high-quality gear to its customers.
Each pack is meticulously inspected by Bonfus co-founder Stefania before shipment – a level of quality control that is unmatched even among cottage ultralight brands.
Each pack is meticulously inspected by Bonfus co-founder Stefania before shipment – a level of quality control that is unmatched even among cottage ultralight brands.
| SIZING | |||
|---|---|---|---|
| SMALL | MEDIUM | LARGE | |
| Torso Length | Up to 18 in 45 cm |
Up to 19.5 in 50 cm |
Up to 22 in 56 cm |
| Hip Belt - Hip Size* | 29.5 - 39 in 75 - 100 cm |
33 - 43 in 84 - 110 cm |
33 - 43 in 84 - 110 cm |
| Pack Weight | 27.7oz 785g |
28oz 795g |
28.5oz 805g |
*Note on hip belt sizing: measurements refer to hip girth at the height of the iliac crest (not waist girth, which tends to be smaller)
Choosing the correct torso size will make your pack sit more comfortably and adapt to your back.
For guidance about how to measure your torso length please refer to our guide.
| SPECS | |
|---|---|
| Volume | 55L (47L internal, 8L external pockets) |
| Suggested Carry Load | Up to 40lbs 15kg |
| Taped Seams |
|
| Ice Axe Loop |
|
| Pockets | Two large side pockets Spacious front mesh pocket |
| Unrolled Height | 34.5 in 87 cm |
| Average Circumference | 38 in 96 cm |
| MATERIALS | |
|---|---|
| Main Body | Ultra 200X for cutting-edge durability and performance |
| Pack Bottom | Reinforced Ultra 400X for abrasion resistance |
| Side Pockets / Shoulder Straps / Hipbelt | UltraGrid Fabric |
ADDITIONAL INFO
Due to the shipping bulk created by the curved frame, the Aerus backpack may be delivered unassembled.
Assembly Instructions for the Aerus Backpack
- 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.
- 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.
- 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.
- 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.
- 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.
- Ultra 200X (130gsm | 3.85oz/sqy): Probably the most advanced pack fabric on the market. It features woven 200D UHMWPE fibers. With only a slight weight increase compared to DCF2.92, Ultra 200X offers 3× higher tear strength, 3× higher UHMWPE fiber content, and 7× the abrasion resistance. The fabric backing consists of a 0.75 mil recycled polyester film with an X-grid, making it extremely waterproof. This fabric is used as the main pack material.
- Ultra 400X (168gsm | 4.95oz/sqy): Constructed with woven 400D UHMWPE fibers and backed with a 0.75 mil recycled polyester film and X-grid for excellent waterproofing. It provides roughly twice the abrasion resistance of Ultra 200X and is used in the bottom section of the pack.
- UltraGrid (146gsm | 4.3oz/sqy): UltraGrid™ is woven with 210d recycled nylon yarn made from pre-consumer industrial waste. A double 5 mm 200d Ultra grid ripstop delivers exceptional tear strength and visual impact. The fabric is treated with a C0 DWR finish that contains no fluorocarbons (PFC-free) and is finished with a waterproof 1500 mm PU backing. Bluesign® approved.
Choosing the correct torso size will make your pack sit more comfortably and adapt to your back. For guidance about how to measure your torso length please refer to our guide below.
Generally, most people will have a torso length in the range 46-54cm (18″-22″).
If you fall into two pack sizes, choose the larger size. A pack that is too small will transfer too much weight to your shoulders.
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