Phelps has chosen to stick with his traditional Speedo suit since he has been sponsored by them for years and earns millions of dollars from the company.
From FOX Sports.com:
"I know he's making a lot of money from Speedo," Cavic said. "It's loyalty. But throughout all my experiences, I've learned this — free will is a gift with a price tag, and whatever you choose to do you're going to pay, but how much you're going to pay is really dependent on you."
Cavic said Arena would provide Phelps one of its polyurethane suits "within the hour." The X-Glide and a similar suit by Jaked are considered fastest at these championships, where a staggering 29 world records were set through the first five days.