One size fits most (velcro back). 
Technical surf Cap. 
Lightweight quick dry material, 
Invaluable protection from harmful sun exposure, 
Minimizes annoying glare, 
Stiff front brim to keep clear vision also flips up for paddling, 
Padded neoprene head band, 
Adjustable quick release chin strap, 
Side mesh vents release water after duck dives and wipe-outs, 
Velcro head adjustment, 
Attach wetsuit zipper webbing to velcro head adjustment for added security, 
Protective mesh over ear section