A helmet designed for water, providing safety to performance athletes moving at ever increasing speed. The H1(TM) Helmet uses a combination of thin EVA and impact resistant ABS to provide an extremely lightweight design. The thin profile ensures very little air turbulence around key areas like the ears and the back of the head to avoid discomfort. The crown of the head has been moulded allowing air to circulate, regulating temperature and encouraging drying. The H1(TM) Helmet comes with varying thickness skull-pads to ensure the helmet fits correctly. These skull-pads are lined with Zhik HydrobaseA(R) material that will wick moisture away from the skin ensuring the helmet feels dry. An adjustment cog system on the back of the helmet allows the user to tighten the helmet around the head for the perfect fit and feel. HELMET SIZE CHARTAll sizes come with extra padding inserts.SIZEHEAD CIRCUMFERENCE-XS51 - 53 cmS54 - 56 cmM57 - 59 cmL60 - 62 cm