Helmet with carbon cage and adjustable fit system

A helmet, comprising:

• an outer shell;
• an impact absorbing layer adjacent to the outer shell;
• and
• a fit system mounted to the impact absorbing layer, wherein the fit system includes:
• a rear portion that includes a rotational mount having a ball and an extension mounted to the ball;
• a rear mount that includes a plurality of grooves, wherein each groove in the plurality of grooves is a curved channel that includes a first portion, a second portion, and a third portion that are fluidly connected, wherein the first portion extends parallel to a line that extends from a front of the helmet to a back of the helmet, the second portion is perpendicular to the first portion, and the third portion is parallel to the first portion, wherein each groove in the plurality of grooves is configured to removably receive the rotational mount of the rear portion of the fit system, wherein the ball rotates within the groove of the plurality of grooves, wherein the ball and the groove are shaped such that downward rotation of the ball within the groove lowers the rear portion of the fit system into a first position in which the rear portion of the fit system extends downward from a bottom of the helmet, and wherein the ball and the groove are shaped such that upward rotation of the ball within the groove raises the rear portion of the fit system into a second position in which the rear portion of the fit system does not extend below the bottom of the helmet.