Totally waterproof - glue sealed seams, big oval shaped brim to give you extra, protection at the front and back. If it looks good on me, it will look good on everyone"- Colin. 7.5cm brim, crown has a black poly/cotton liner, sweat stop terry towelling headband, covered ventilation eyelets (i.e. under a flap of fabric to stop any water penetration), thin elastic chinstrap, which remains in the, crown when not required.