CUSTOM-made, crocodile sneakers coated in gold may not be your average shoe but APL is hardly your average sporting brand.

Athletic Propulsion Labs (aka APL) is a Los Angeles-based luxury performance sneaker label regularly seen on the Kardashians, Jessica Alba and even Oprah.

But APL’s range includes a level of luxury even the most famous family in America doesn’t own — $US20,000 ($AU28,000) runners.

Dubbed the “Lusso Supreme”, the insanely expensive APL shoes are painted with 24 carat gold and strictly made to order.

“We don’t even have a pair of them,” said APL co-founder Ryan Goldston. “They are on display in the office. They’re made to order,” he said, adding that the crocodile leather is soured from the “same farm that Hermes uses for Birkin bags”.

“We were looking for an innovation in the luxury space, where we could really create something and own the market.”

While Ryan and his fellow APL co-founder, twin brother Adam Goldston, would not reveal specifics about sales of the $A28,000 sneaker, he said the brand had days where they had sold “multiple pairs through our website”.

The Goldsten brothers are in Melbourne to launch APL’s newest collaboration — this time, with Australian fitness powerhouse F45.

Sold exclusively at F45 studios in Australia, the $270 shoes are designed with the gym chain’s 45-minute workouts in mind.

Based in an all-white studio in downtown LA, APL — which the Goldston twins started in their college dorm at the University of Southern California — has a huge celebrity following, and have been worn by just about every Kardashian.

“One of the men’s buyers at Saks Fifth Avenue told us there were guys coming in asking for the shoes that Kim Kardashian was wearing, referring to APLs,” Ryan said.

“Their impact stems that far (to men). They were like, ‘I know you carry APL … I want the ones that Kim was wearing.’

“It was enough for them (Saks) to bring it up and tell us.”

Adam chimes in: “We’ve never paid anyone a dollar to wear our shoes”.

“That’s how we built the brand,” he said. “We’ve built relationships with them (celebrities) at this point, but a lot of them bought the product first … we’re not actively trying to find people to give shoes to.”

While many other sporting brands are logo-focused, part of the appeal of APL is the subtle branding.

“Most people don’t want to be a walking billboard,” Adam said.

“On our shoes, if you look at them from the side, there’s no huge branding on it.”

The technologically-driven APL designs are so advanced that their shoe was banned from the NBA.

“We have a patented technology that is a compression spring-based system that sits in the forefoot, and that technology which is called ‘load and launch’ instantly makes you jump higher,” Ryan said.

“We did all the testing … guys off a college campus got a up to a 3.5 inch (8.9cm) increase instantly. And so that technology is what they (NBA) banned because they said it provided an undue competitive advantage.”