GIRO Source Mips Helmet MTB Helmet The Source Mips® helmet combines advanced performance and protection in a rugged, trail-ready design. Details Capably equipped for fun and adventure The Source Mips® helmet combines advanced performance and protection in a rugged, trail-ready design. Featuring deep coverage with aggressive ventilation from 17 vents coupled with deep internal channeling, it helps keep things cool even when the riding gets rowdy. And with the comfort and secure feel of the Roc Loc™ 5 Mips fit system with Integrated Mips brain protection, plus a moto-style adjustable screw-in visor and full lower Hardbody durability, you get a helmet that's capably equipped for fun and adventure. Specs CONSTRUCTION FULL-WRAP IN-MOLD POLYCARBONATE SHELL WITH EPS LINER VISOR ADJUSTABLE MOTO-STYLE SCREW-IN VISOR VENTILATION 17 VENTS WITH DEEP INTERNAL CHANNELING FIT SYSTEM ROC LOC® 5 MIPS® PRODUCT WEIGHT 351G (SIZE MEDIUM CPSC)|340G (SIZE MEDIUM CE) CERTIFICATION COMPLIES WITH THE US CPSC SAFETY STANDARD FOR BICYCLE HELMET FOR PERSONS AGE 5 AND OLDER E.U.: CE EN1078 HIGHLIGHTS COOLFIT™ PADDING ADULT SUPER FIT SIZE CIRCUMFERENCE S 51 - 55 cm M 55 - 59 cm L 59 - 63 cm XL 61 - 65 cm Note: We recommend you try helmets on before buying. Make sure the helmet fits with a little room when the fit system is loose, and sits low enough to protect your forehead without hindering your vision. Once you’ve got the right size, you can adjust the fit. HOW TO ADJUST THE FIT Step 1: Adjust the fit system at the rear of the helmet for a snug, secure fit. Some helmets also include a vertical tuning feature that allows you to adjust the fore/aft tilt, for optimal positioning on your head. Step 2: Adjust the straps so that they sit just below the earlobes. Step 3: Adjust the buckle so that it rests against the back of the jaw/throat. Step 4: Adjust the interior pads if needed. Step 5: Check the fit to make sure helmet is comfortable and secure. It should not roll forward or back, or be able to slide off.