Totally waterproof - glue sealed seams, folds to pocket size, for those times when you are caught in the rain compact, easy to carry, 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 size adjuster is on the outside of the cap, therefore no water penetration.