I am offering my Giro Aerohead Mips helmet in size M, suitable for a head circumference of 55-59 cm. This helmet is ideal for triathlon and time trial rides, as it is designed for aerodynamics. The original packaging is included. I only wore the helmet once before switching to a different model because my position on the bike changed. It has not been involved in any crashes and has not been dropped, so it is in mint condition.