ʻO nā valves counterbalance hydraulic kahi ʻano o ka valve i hoʻohana ʻia e kāohi i ka kahe o ka wai i loko o kahi ʻōnaehana hydraulic. Hoʻohana maʻamau ia i mea e pale ai i ka hoʻonui ʻana i nā ukana, hiki ke hōʻino i nā mea hana a i ʻole nā ​​​​hōʻeha.