Surf champ Kelly Slater didn’t just test the latest board shorts for his brand Outerknown — he also helped design them himself.

As the second generation of the brand’s Apex trunks, Outerknown’s Apex Evolution Surf Trunks are the result of years of testing to meet Slater’s highly specific demands. In addition to three upgrades requested by the surfing GOAT himself, the upgraded trunks are supposedly the first four-way stretch surf shorts made from Bureo’s popular NetPlus material.

Bureo crafts new fabrics from post-consumer recycled fishing nets through 100% recycled and 100% traceable practices. It works with companies like Patagonia, Yeti, and REI to keep fishing net waste out of oceans, and uses those recovered nets to make sustainable garments and gear.

While this practice isn’t new (Patagonia has supported and used Bureo’s NetPlus materials for over a decade), these trunks might be one of the first pieces of apparel to use NetPlus with four-way stretch. It’s a design that Outerknown says took more than 3 years to perfect.

Second-Generation Upgrades

Kelly Slater and John Moore, Outerknown’s creative director, started the surf-based company on the premise of sustainability and high performance. Relying on the previous Apex trunk design, Slater says he wanted three upgrades: better no-slip braided drawcords, a better waistband that cinches without bunching, and reinforced ultrasonic-welded seams for less chafing.

Moore claims that Kelly’s requests boosted this upgrade to “the highest performance trunk ever made.”

Bringing Recycled Nets Back to the Water

Bureo collects discarded fishing nets directly from fishing communities before the nets end up as ocean trash. Lost or ripped fishing nets, Bureo says, are one of the most harmful forms of ocean pollution.

Both Bureo and Outerknown claim that the Apex Evolution trunks are made from 90% recycled NetPlus nylon and 10% spandex. Outerknown worked closely with Bureo for over 3 years to ensure the NetPlus materials could perform the way Slater wanted, according to the brand.

Slater says he tested three prototypes of the new Apex Evolution trunks in Hawaii, Fiji, Tahiti, and beyond. Each locale offered different temperatures and sizes of waves.

Outerknown ambassadors tried out variations, as well, and over the course of 3 years, the Apex Evolution Trunks evolved into today’s product. Pro surfer Kevin Shulz claimed the shorts needed zero break-in. After 2 hours of surfing, he stated he was still rash-free.

Where to Find Apex Evolution Trunks

The Apex Evolution trunks are available in eight different 19-inch styles now; 17-inch designs will be available in early April.