In February I used a Silo 52L on two 10 day backcountry ski tours of Norway. Daily skiing was between huts in the brilliant DMT hut system, where you can replenish food on a daily basis at each hut, reducing the requirement to backpack food for the whole trip. I would agree with Greg Hill's comment about a 1 to 3 day adventure carrying capacity limit.

I can't speak highly enough of Arc'teryx ergonomic and well thought out designs including their use of materials, and have placed my faith in their equipment for the last 7 years. I used to own an earlier Arc'teryx model called the Khamski pack which this one has replaced.

Very functional, excellent form and fit for skiing. Comfortable harness and load bearing.

Living currently in Perth, Australia, the climate has put me off buying a pair, however with trail runs planned in the Colorado Rockies, and New Zealand Southern Alps again this year, I jumped at the opportunity to buy a pair in a recent sale. I usually trail run with two interchanging pairs of XA Pro 3D Ultra without goretex, and the goretex construction in comparison makes for a more supportive shoe.

This week I had the opportunity to trial them on a 2 hour trail run when the temperatures dropped to 22-26 degrees Celcius. This may seem warm for goretex, but they stayed dry and very comfortable for the duration.I even wore them for the 1 hour drive home from the trail run location on the Bibbulman Track without considering taking them off.

I was surprised at how breathable they were and like any goretex products you need to keep them clean to properly function.

The run was through some nasty and extreme jagged rocks and loose gravel and my feet were well protected. Technically a great shoe that fits me and I am looking forward to testing it on a rainy and wet day for further feedback!

I am a trail runner and for the last 4 months I have tested the XA Pro 3D Ultra 3 days a week on runs approximately 26 - 30kms in length over some tough shoe wearing trails; mix of sand, sharp rocks, elevation and loose gravel. They still feel comfortable, are intact and gave me reason to buy another pair last week.

First and foremost they fitted me in the shop. I wont buy any shoes unless they feel right 100%. In comparison the WT model felt slightly tight on the sides of the toe box which in no uncertain terms would have meant pain on the trail; dont let the salesperson tell you otherwise!

When trying on shoes make sure you team them up with the socks you intend to wear. I have found Ultimax silver socks are good for temperature regulation and moisture wicking and work well with the XA Pro shoe material.

The lacing system is tough, quick and efficient and holds at the selected personal setting. Make the most of the lacing system to tighten or loosen off when your feet tell you.The excess lace and toggle fit well in the mesh pocket on the tongue and don't fall out.

The shoe gives good support and protection on rocky trails. Of note when you look at the rubber toe box after a run you can see scuff marks from rocks as high up as the logo, which fortunately you didn't feel thanks to the well thought out ergonomic design.

After a run on the dry trails my shoes, socks & legs are covered in brown dust and grit. Take out the insoles, shake out any loose material you have picked up, and carefully wash the outside of the shoes then the insides. Give the insoles a tap and wash as well. Inspect and then wash with a mild detergent and brush. Your shoes will last a lot longer and your tough trail buddies will do the job they were intended for.

For me the XA Pro 3D Ultra are winners, so if they fit you give them a go.