The sealing element is a metal piston with ring-shaped seat seal. Valve design with piston guide bands and grooved ring. Suitable for a wide range of applications due to the use of different sealing and housing materials. Due to the shape of the piston, the valves usually build up higher than diaphragm valves. However, differential pressures of up to 40 bar can be switched with Type 24, and up to 100 bar in special versions. Screw-in valve seat made of stainless steel is obligatory. Very large variety of options.