SONRO is a streetwear brand that is well-known for their unique cap design. Many korean celebs use SONRO caps. I don’t know what is ‘supersonic project’ that Yeon Jung Hoon talked here but it seems Yeon Jung Hoon has a collaboration with them for this cap design. Maybe it has something to do with Ferrari because I can see Ferrari logo on it & we might get to see him wearing this cap in future!
Credit: Yeon Jung Hoon instagram jeffyoun