Spring into action with the 100% polyester flatbilled and adjustable Avengers AoU Captain America 9Fifty Snapback Cap! I say spring into action because let's be honest...Chris Evans' character tends to have that effect on people. Produced by New Era and from a combination of polyester and cotton, the Avengers AoU Captain America 9Fifty Snapback Cap is one of the coolest hats inspired by Marvel's Age of Ultron! Sometimes you need a little old fashioned.