bouncepro 14' round trampoline vertical leg extension with holes (6b) bounce pro keep your trampoline in the best working condition by replacing your vertical leg extension. the bouncepro 14' round trampoline vertical leg extension with hole (6b) is part of the leg frame assembly. the leg extension connects the top rail with the leg base. the 6b leg extension has larger, indented holes that will attach to the lower frame tubes. this trampoline model has six vertical legs. length: 26-inches.