Ashcroft pressure gauges are designed to measure the pressure applied on a surface by a fluid and are used as replacement gauges on filters. They alert the operator to replace the filter canister when the pressure drops below a certain level. These pressure gauges feature a circular dial with readings, calibrated to provide data with an accuracy of +/-0.25%. The needle and scale are protected by glass or polycarbonate clear lenses. These pressure gauges are available in plastic, aluminium & stainless steel cases on Raptor Supplies.