1,No need connect with electrical source and air source 2,Light and ... area, adding hydrostatic pressure, then we can know the pressure the tested object bore through the pressure gauge ,and we ... object is qualified under the pressure. Feature:1, No need to connect with any electrical source and air source.2, ... rubber ball manually.4, Cable of testing hydro pressure up to 10000 mmH2O.5,Water in the tank ...