These DRSskate/BMX helmets look awesome. The new standard in protective gear. Features Heaps great colours choices New shape for better fit and styling 14 vents so cool heads always prevail 2 sets of sizing pads Helmets meet Australian standards for bicycle helmets. To measure, grab tape measure and measure the circumference of your head or your child's head just above the eyebrows, this is the best place to measure, match the cm measurement to the measurements below to know what size you are.