Rocker hurdles are built to "rock" when hit so younger hurdlers are not thrown off balance or injured. Designed for middle and high schools, they're ideal for teaching beginners. FIRST PLACE COMPETITOR ROCKER HURDLES are the strongest and best rocker hurdles made! GILL #411 SCHOLASTIC ROCKER HURDLES are traditional hurdles with slightly thinner construction. Both hurdles adjust to 30", 33", 36", 39" and 42", meet NFHS rules, are available with various color uprights, and can have custom screening with a school name.