The M4 is an aggressively styled, multi-featured, full-ventilation helmet with an extra large eyeport that offers improved driver vision and ease of using most forms of eyeware. Styled after the M4 Pro, the M4 can be used in all forms of racing. In addition, the M-4 features Bell's new SRV friction shield system. This new system has a slide mechanism that allows the driver to adjust the tension on the shield allowing for multiple opening positions. When properly adjusted and in the locked position, the SRV systems helps reduce the possibility of the shield opening during an impact. SA2005 Certified