Atara Mt Gl BlackAtara Mt Gl Black SIZING S51 56 cm20 22 M55 59 cm21. 6 23. 2 L58 61 cm22. 8 24 The ATARA benefits from all of the technical development of HJCs high end models such as the IBEX 2. 0 and Furion 2. 0. Aerodynamic and comfortable, the ATARA is your perfect entry into the world of HJC, an everyday helmet with a perfect fit. It is light in weight, easy to adjust to your head size and makes no compromise on security.