The wafer construction of the device does have a flow- optimised flap and requires therefore only max. 1/3 of the internal cross section. The axles are extremely oversized and therefore do not need any counter bearings. Depending on the application, the meters can be equipped with plain, ball or spherical bearings and / or with shaft seals. For use in aggressive liquids Hastelloy as well as various plastic versions, e.g. PTFE or PP are available.