Billionaire investor Warren Buffett has high praise for Apple, calling the iPhone maker “probably the best business I know in the world.” Speaking on CNBC’s “Squawk Box,” the Berkshire Hathaway CEO hailed the tech giant as the holding company’s third-biggest business, behind its insurance and railroad stakes.

In his annual letter to shareholders, Buffett revealed that Berkshire Hathaway holds a 5.7% year-end stake in Apple. This equaled roughly 245 million shares valued at around $72 billion. With the stock climbing 80% in the last year, Buffett said that his only regret is not embracing the company earlier.

“I should have appreciated it earlier,” Buffett said.

Berkshire Hathaway acquired its first 10 million shares of Apple stock in May 2016. By May 2018, the company held 165.3 million shares and bought 75 million more shares.

Appropriately, with his newfound faith in the company, Buffett also revealed that he had finally moved past a flip phone and begun using an iPhone.

“You’re looking at an 89-year-old guy who’s barely beginning to get with it,” Buffett said.

While he has finally moved on to a smartphone, the CEO admitted that he mostly uses to make phone calls only. He also uses an iPad to conduct research and track stocks.

In Buffett’s view, the iPhone’s ubiquity makes Apple a favorable company, with its utility increasing as it continues to reach wider audiences. He also explained that he sees the Cupertino, California-based business as less of a technology company and more of a consumer product one.