WAA MDS Ultrabag Review

I recently got a 20L WAA MDS Ultrabag. This is the official backpack for the Marathon de Sables, a 6-day, 250km foot race through the Sahara desert.

WAA MDS 20L Ultrabag

I have no plans to do that race, but do intend to go on some multi-day adventures here in Japan. So far, I have used the bag for a 52km trail run and an 86km road run.

I’ll assume that you’ve already researched the Ultrabag and know what it is and what accessories it comes with. If not, read up the feature list from the store I bought mine at.

Don’t like reading? Here’s a 20-minute video I made about the Ultrabag.

First impressions

The bag arrived in one piece, and by that I mean that all the accessories were pre-attached, and since there weren’t any instructions, I carefully remembered what connected to what before taking it to bits.

Once everything was off, I weighed the main pack at 576g, a touch less than the advertised 590g, and there are still a lot of small shock cords that could probably come off, too.


I then unwrapped the bottles and spent a good while figuring out how the straws went through the caps… turns out you need to push them through with brute force and pull them out the other side with your jaws. Well, at least there shouldn’t be any leaking! Actually, I haven’t used the bottles yet. It’s still early in the year as I write this and have no need for massive 750ml bottles. Plus, each straw is too long when the bottle is on the shoulder strap, and too short when the bottle is on the side of the main backpack. I’ll probably cut the straw for use on my shoulder, but am using my old Ultimate Direction bottle for now.

Trekking poles

I really wanted to know how my Berghaus trekking poles would attach to the pack. The advertising says you can put “walking sticks” in the long, cylindrical pocket on the back of the pack, the one that’s supposed to be for the MDS flare. My poles are of the telescopic variety, and I could quite easily get one in that pocket, but just one. I’d have to take the pole baskets off to squeeze them both in.

A better solution was to attach them outside that pocket with the existing shock cord and elastic loop. Excellent, except you have to take the pack off to get to them, which is not so easy to do with a technical pack like this – there are four buckles to unclip to take the pack off with the front pouch still attached to one side.


I haven’t used the side pouches or the shoulder one yet. The 4L front pouch is amazingly convenient so I just threw everything in there. The contents shake around a bit because the compression straps don’t really compress the whole pouch down, but it’s manageable and very comfortable when used with the main pack. I did try using it by itself on a short trail run, but the bottle I attached to the side swung around terribly, and it bounced a lot when strapped on top of the pouch, too. I really do like the front pouch for convenience, though, so I will definitely be using it for my long runs.


This pack is loaded with straps. You can adjust almost everything to get the perfect fit, and it’s really comfortable to run with. If you’re skinny like me, you’ll probably have unnecessary straps hanging all over the place. There are elastic loops to tuck these into, but I couldn’t be bothered to keep folding up and tucking the straps away every time I took the pack off and put it back on again, instead opting to stuff them behind the front pouch. Much easier. Of course, you could probably cut the straps shorter and save some weight in the process.

Bottle holders

My biggest disappointment with the MDS Ultrabag is the bottle holders. They look great, but are useless for anything except their intended purpose, that is holding a bottle in place. If you’ve ever used an Ultimate Direction Ultra Vest (I have an SJ one), you’ll love how the bottle holders are a bit baggy, but with shock cord elastic around the top so you can easily stretch them open to put your bottle in and tightly secure them in place. Indeed, you can even use them for other stuff like sweets or a camera. They are very easy to use on the go, even while running, without having to look at the pocket.

The WAA bottle holders, on the other hand, are not stretchy at all. They fit the WAA bottles perfectly, but that means they are a pain to get the bottles into because you can’t even squeeze a finger between the bottle and the mouth of the holder. There are two straps you can use to tighten the holder around the bottle, but these are a bit short and hard to use on the run. I can imagine time lost at aid stations messing about with these holders, even if you choose to use the straws… though I suppose in the MDS you could just leave the bottle in the holder, unscrew the cap and refill the bottle while it’s still on your shoulder strap. Actually, writing this has helped me figure out what to do: I’ll cut the straws of the WAA bottles to a comfortable length, and unscrew the tops off for refilling. Why didn’t I think of that before?!


The main backpack is rectangular and somewhat shallow. It doesn’t use any stretchy material so I was worried how easily I could pack everything. So far, I’ve been able to put in a small tent, sleeping bag, emergency bivvy, full rain wear and a change of clothes. My sleeping mat is strapped under the pack so I just need room for a camping stove, which I’m hopeful I can squeeze in.


This is a great pack. It fits well, is comfortable to wear and I love having a spacious front pouch to throw stuff in. I don’t think it’s perfect, but it’s the kind of pack you can customize to make work for you, and I like that a lot.

If you like, you can find me on Twitter at @nick_ramsay. I'd love to hear from you!