Adjustable speed hurdles give you all the benefits of the regular fixed hurdles but allow you to increase the height by 6”. Simply swivel the height extension and you can increase the height of the hurdle up to 6”. The extension converts the 6” hurdle into a 12” hurdle and the 12” hurdle into an 18” hurdle! These hurdles are manufactured from Polypropylene. They are hard wearing and eco friendly! Available singularly or in sets of six. Further Description: Red 12" hurdle with 6" extension.