FEATURES: Full hardbody shell Roc Loc Sport MIPS fit system offers easy one-handed adjustments for a comfortable fit Ventilation: 18 vents In-mold construction fuses the polycarbonate outer shell with the EPS foam liner Ponytail compatibility TECHNOLOGY: Multi-Directional Impact Protection System (MIPS) reduces rotational forces from certain impacts for more protection SPECS: Universal sizing: 19.75" - 22.5"