Many backpacks have options to carry water, but hydration vests are designed around it.

When ultra runner and author Scott Jurek sets out to do something, he does it, like setting the world record for running the entire length of the 2,200-mile Appalachian Trail in 43 days. And he did that wearing a hydration vest that he designed with running gear manufacturer Ultimate Direction. We take a look at the 2016 Ultimate Direction Scott Jurek Signature Series Ultra Vest 3.0, to see what it’s all about.

1) Where did it go?

As promised, this vest, at 10 ounces, is very light. It feels like it’s not even there. Considering it is a vest, it has a whopping 8.5 liter volume, or 641 cubic inches. We were surprised how well it carried weight, especially up front.

2) All access

With cool stretchy pockets, six up front and two in back, it accommodates everything from water bottles to electronics, food and other items. Everything is easily accessible, even the zipper pocket around back. One clever pocket high on the harness is waterproof.

There is a practical bungee cord system to carry foldable trekking poles up front and a rear pouch can take a 2-liter water bladder. An exterior bungee strap secures even more stuff.

3) Bottled water

The two included 17-ounce soft water bottles are sweet, although a little different than what many people may be accustomed to. They’re meant to be squeezed, jetting water out. Their soft construction conforms to your body well, even they’re a little finicky to stash — a draw cord is there to snug them up.

When the water is gone, they seem to just disappear.

4) Chafe-free

The micro-mesh material is comfortable against the skin. There seem to be no hot spots and it breathes well.

In fact, According to Jurek, he ran shirtless during much of his Appalachian Trail run.

5) Three sizes fit all

While the vest comes in three sizes, it is extremely adjustable. Lateral straps allow a huge degree of variability allowing a precise fit, and up front nifty T-clip chest straps provide adjustable stability.

So long as you cinch things down, this vest delivers as promised: light, stable and comfortable. Look for these vests all over the trail and running circuits.

Starting cost: $124.95