S1 helmet co are an independently owned and operated brand that is deeply rooted in the californian skateboarding longboarding bmx and roller derby scenes today s1 helmet co has an extensive line of protective helmets that are rapidly becoming known throughout the industry thanks to their unrelenting approach to style and safety the s1 lifer helmets offer up to 5 times more protection than regular soft foam skate helmets and offers a superior fit small 53 3cm 21 medium 54 6cm 21