The device operates largely independently of viscosity and is suitable for flow indication of water, acids, alkalis, and gases.

Each device is calibrated according to customer requirements and provided with a medium-specific scale.

Inside the 50 mm ring, a semicircular plate is mounted on a rotatable spring-loaded axis. Depending on the flow rate, the angle between the flap and the ring changes. A fail-safe magnetic coupling transmits the movement to an external pointer (operating principle).

For process control, the device can be equipped with limit switches or a signal converter with an electrical analog output.

The standard indicator is designed as a round stainless-steel housing with bayonet lock and can optionally be fitted with limit switches. The indicator unit with integrated 4–20 mA output is housed in a die-cast aluminium enclosure.