Be ready for your next swim competition in the Nike Men's HydraStrong Solid Jammers. These swim jammers are made of Nikeâ⢠HydraStrong fabric with a polyester lining to provide long-lasting durability. They are designed to combat water resistance during competitions and feature an interior drawstring that is adjustable for a secure fit. Nike Men's HydraStrong Solid Jammers Midnight Navy Blue, 26 - Men's Competition Swim at Academy Sports