Fabric guide
I work with premium fabrics from X-Pac®, ECOPAK™ and Dyneema®. These fabrics share three essential qualities: durability, water resistance and light weight. Combined with exceptional workmanship and attention to details, these materials help delivering the best gear possible.
All these fabrics all laminates and offer better protection, lighter weight and they last longer than traditional coated fabrics.
X-Pac
High-performance fabric. Lightweight, durable, and 100% waterproof. Eco-friendly and carbon neutral.
VX21 and VX42 are the most versatile, depending whether you want to keep the weight low or you seek extra abrasion resistance. X50 is more rugged, has more classic look, it's heavier, and UVX40 offers the best performance.
Read more at https://www.x-pac.com
Ecopak
Waterproof, durable and lightweight fabric with 100% recycled polyester and non-toxic DWR coating. Every yard of ECOPAK™ uses about 20 plastic bottles and saves one pound of carbon emissions compared to standard fabric. If you care about the environment, Ecopak is the way to go.
Choose EPX200 if you want lightweight backpack. Heavier denier and weight mean increased durability at the expense of weight. EPX400 is therefore heavier, but more abrasion resistant.
Choose Ultra fabric if you’re looking for an ultralight backpack solution with the ultimate, most high-end fabric.
UltraX line vs. UltraTX line
Ultra consists of 67% U-PE and 33% polyester woven together and laminated to waterproof film. UltraTX is a result of combining Ultra with Ecopak - 67% U-PE and 33% polyester with waterproof fabric, CrossPly and white 70D ripstop protective backing. UltraTX brings the best of the two worlds together - outstanding abrasion resistance thanks to the U-PE face fabric, better stitch holding, longevity and good visibility thanks to the white backing, and better strength.
Choose Ultra if you want a truly ultralight solution or UltraTX for the best-performing fabric available.
For 2023, there's a new style available: Ultra100X, Ultra200X, and Ultra400X, which replaced the previous Ultra collection. It has black Ultra fiber crossply but doesn't have the white ripstop backing like UltraTX. It makes the fabric little stronger and more stable (especially in bias direction).
Read more at:
https://challenge-outdoor.com/ecopak
https://challenge-outdoor.com/ultra-collection
https://challenge-outdoor.com/ultra-grid
https://challenge-outdoor.com/ultra-stretch
2025 update:
Ultra100X Charcoal Grey and Ultra200X Storm Grey added as options. I also plan to get Ultra200X White later this year. Check Challenge Sailcloth website for all the colors.
Ultragrid colors
X-Pac vs Ecopak
In terms of performance, Ecopak manages to have slightly better abrasion resistance while being about 10% lighter compared to its X-Pac counterparts at the same weight. In real life, you most likely won’t be able to tell the difference though.
In terms of touch and feel, Ecopak feels a little softer, similar to slightly broken in X-Pac. If you want more technical look and feel, choose X-Pac.
If using recycled fabric and using non-toxic coating is import to you, choose Ecopak.
If you want to read more about Ecopak and X-Pac, you can find a good article at thetrek.co.
UHMWPE
UHMWPE (also U-PE) stands for Ultra High Molecular Weight Polyethylene and translates into high end fabrics made with the strongest and lightest fabrics in the textile industry. These fabrics a go to when you want the best fabric – the strongest and the lightest possible.
In this category you can choose from Ultra100, 200, 400 and 800, Ultra100X, Ultra200X and Ultra400X, Ultra200TX and 400TX, and UVX40. I might also have some Dyneema in 2.92 oz or 5.0 oz variant but I don't stock these regularly.
Other materials

I don't make compromises, it's simply not worth it. I work with the best materials possible and pay attention to the smallest detail. Metal hardware, YKK zippers, Fidlock magnetic buckles, Cobra buckles, YKK, Duraflex, Wetool, Woojin.