This vintage men’s swimsuit was made in the 1950s by Campus Sportswear. They are cotton with racing stripes down the side seams. They have a flapped key pocket and an elastic waist. The front is lined. The elastic in the waist is still in great shape and stretchy. Some light stains from storage, but I think they would come out. They are tagged a size 30-32

Waist unstretched: 10″ (doubled = 20″)
Waist stretched: 15-1/2″ (doubled = 31″)
Rise: 11″
Side Seam: 7″