The overdrive is a performance mountain bike helmet with superior ventilation, removable visor and the TS+ dial fit retention system (use the adjustment dial at the back to customize the fit of your helmet). 21 large vents help manage heat on extra hot days, adding comfort to protection. The overdrive is perfect for mountain bikers looking for a high performance helmet that stays comfortable and secure all day. Instructions to measure your head: -use a soft tape meaance helmet that stays comfortable and secure all day. Instructions to measure your head: -use a soft tape measure the circumference (around) your head -if you don’t have a soft tape measure a piece of string or yarn is a good substitute, make sure to have a ruler or tape measure handy that is at least 24 inches (or 2ft.) long -measure your head just above your eyebrows, make sure the tape or string is level from front to back -if the measurement is between 52cm-57cm you need a MD helmet -if the measurement is between 56cm-61cm you need a large helmet.

Specifications: