The EPP-40V is specifically designed for measuring pore water pressure in small diameter boreholes and standpipes. It is made of stainless steel with a built-in thermistor for temperature measurement and surge arrester for protection from lightning. For an easy cable connection a glass to metal solder pin connector is provided. The sensor is hermetically sealed with a vacuum of around 0.001 Torr inside it. A low air entry value ceramic flat filter is provided with a grain size of 40-60 microns unless specified otherwise.