Mounted in sapphire bearings, helix rotates to align with magnetic field of magnet and transmit pressure indication to pointer. Zero adjustment screw is conveniently located in plastic cover, accessible without removing cover. Range spring calibration is screw adjusted. Rate adjust and rate adjust lock are coaxial and are factory set and sealed. Precision made case is offered in two materials.
Standard is die cast aluminum coated inside for resistance to most oils and similar fluids.
Optional forged brass case is recommended when using water or water based liquids. Diaphragm motion is restricted to prevent damage due to over-pressure. Double convolution allows choice of effective areas to suit range at time of assembly. Diaphragm support plate of stainless steel minimizes position or attitude sensitivity. Calibrated range spring is a flat leaf of stainless steel.