Triathletes have different needs from their helmets and the Tardiz II helmet is designed for Triathlon and like the Dr's phone box will help you move through space and time. - Triathlon Specific- Aquavant- Quick and Easy to get on and off- More Aerodynamic than a standard road helmet The Tardiz II is a cross between a TT and a road helmet with a focus on the needs of triathlon tt has the aerodynamics of a TT helmet but combined with the ventilation and comfort of a road helmet. The Tardiz was the first helmet designed exclusively with the specific needs of multi-hour triathlon racing in mind.Aerodynamic performance without the risk of overheating. Vents assure airflow over the riders’ head with an additional Aquavent. The Aquavent is a spring-loaded ventilation port on the top surface of the helmet which allows the option of delivering water into the helmet to prevent overheating. Simply press the vent cover down with your water bottle and dump in cooling water. Special perforated EVA padding and EVS channelling allows the water to filter down the back of your head and not down your face. Optimal water and air flow over the head provides for maximum cooling and riding efficiency. Dual Layer Aerodynamics a front smooth surface and a back dimpled surface provides the best possible airflow over and around the helmet. Soft ear flaps make for a great fit and quick on and offs in transition. Eyewear channels make it easy to fit around your favourite Lazer eyewear without interference between the eyewear arms and ear covers.