an adjusting mechanism alters the heel height on a prosthetic foot , and works independently of any articulating ankle joint or foot style , without changing the original dynamic alignment of a prosthetic leg . in a two chamber hydraulic closed system — a fluid material is allowed to flow through the two chambers by use of pistons that push the fluid material equally from one chamber to another until the desired heel height is obtained . once the correct position is obtained , the ports are closed by use of a push button stop , which closes the ports and stops all transfer of fluid between the ports holding the heel in position during use .