【Kids Dirt Bike Gear for 4-12 Years Old】4 Size Motorcycle Body Armor Jacket ,S for 4-6 YO(height:39.3"-44.1" weight:35.2-48.5lbs), M for 6-8 YO(height:44.1"-48.8" weight:48.6-61.5lbs),L for8-10 YO(height:48.8"-53.5" weight:61.7-77.1lbs).XL for 10-12 YO(height:53.5"-59.8" weight:77.2-92.5lbs).Please refer to the size chart for detailed data.Children Spine Back Chest Protector .