These instruments have been designed for laboratories, instrument testing or recalibration facilities and in other applications where accuracy and repeatability are of primary importance. These intruments have a solid separating wall in stainless steel, placed between the dial and the elastic element and an integral blow out back that is released from the case whenever a pressure is created inside the case, due to leaks or accidental ruptures of the elastic element. Thay can be used with fluids or gasses that do not have high viscosity and do not cristallize. The wetted parts in beryllium copper permits higher accuracy. They are supplied with a calibration report issued by our laboratory and upon request we can supply the calibration certificate issued by an Internationally recognized laboratory of ACCREDIA.