The GR 20 in Corsica is often referred to as the “toughest trek” in the hiking world. But for ultra-runner and The North Face athlete Rory Bosio, it’s just another notch on her belt. Bosio recently ran the 125-mile GR 20 in just 50 hours. She’s a badass runner that spends her days working as a NICU nurse at UC Davis, and runs in the wild on her days off.

As one of the most technical and challenging trails in Europe, the GR 20 required some training, support and top-notch gear. Bosio runs for anywhere from three to five hours at a time and tries to get outside SUP’ing, swimming and cycling as often as she can.

We caught up with Bosio to ask her what gear is crucial for her training, and for taking on feats like the GR 20.

Rory Bosio’s Gear

The North Face Hyperair Gore-Tex Trail Jacket

“I always have this in my pack. It’s a security blanket. It stinks to be soaking wet with hours left to go on a long run. This jacket is the primo lightweight, but fully waterproof jacket.”

DryMax Socks

“The best socks. I never get blisters (or rarely).”

The North Face Runner’s Cap

“I’m firmly in my 30s, and don’t want to look like a vintage handbag when I’m an octogenarian.”

JayBird RUN Wireless Ear Buds

“I love listening to music/podcasts for portions of my trail time. These buds are small and wireless. I dig them.”

The North Face Better Than Naked Shorts

“I exclusively run in these two items [short + skort]. I love the wide waistband and feel of the fabric — it’s lightweight and never chafes.”

Black Diamond Collapsible Lightweight Poles

“When running in the Alps or steep terrain, these break down to about 13 inches long so that they can be stowed in the pack.”

The North Face Etip Runner’s Gloves

“I always have a pair of lightweight gloves in my pack (even in summer), as my hands get cold and that’s the worst!”

SPOT Tracker

“This GPS device tracks your position so family and friends can follow along online. Also, it has an SOS function, so if I’m up shit creek, I can activate search and rescue. I only carry this when I’m really out for a long adventure where I’m very isolated.”

Lara Bars

“I eat a variety of foods while running. In training, I avoid most bars and gels (I always avoid gels. I’m gelled out. It goes in like goo, comes out like goo). In general, I like more whole foods; less science experiment-types of foods with ingredients I can’t pronounce. I like that there are only two ingredients in Larabars: dates and nuts.

Coca-Cola

“Coca-Cola mixed with a little water is my hydration choice, [and it goes] straight into my Camelbak bladder. When I ran across Corsica, I drank 20L of Coke over 2 days. Enough to kill a pony, and make my dentist very rich.”