An electromagnetic meter has no moving parts and nothing protruding into the flow: a magnetic field is applied across the pipe and the voltage induced by the moving conductive liquid is proportional to its velocity. That makes it a common choice for water, wastewater and other conductive liquids where pressure loss and wear matter.
The listings in this family show a compact meter with the converter on the tube, a version with a separate converter box, and a DN50 meter with a choice of outputs. They differ in protection rating and signal options, so each is set out below instead of being merged into one specification.