Help me pick a birthday gift for my surfer boyfriend!

My bf is a "part time" surfer; he loves to surf, but does it fairly infrequently (the beach is a plane ride away) and usually rents a board and other necessary equipment. Can you think of piece of some surfing accessory that costs $15-$45 and that would be easy to transport in a suitcase?
Thanks a million!
Thanks a million!