Designed by Best Fittings, These Air Tank Anti-Roll Transport Cradles are designed to rest your tank on when being transported in vehicles to and from shooting locations. They prevent damage to the tank's fittings valve and fill whips increasing the longevity of your filling equipment. Perhaps you have seen other shooters with damaged fill whips on their tanks this is the thing that these cradles are designed to prevent. For the sake of a small amount of money, these prevent you from having to buy multiple fill lines #(or even full valves) over the course of your tank's life.