They're FM Class I, Div. 2-certified for hazardous areas. Transducers for FM Class I, Div. 1 and 2 are available.

Fluxus F/G 7407316 SE Ultrasonic Liquid and Gas Clamp-on Flowmeters Allow Precise, Bi-Directional, Dynamic Measurement of Volume and Mass Flow Rates of Any Gas and Liquid Media...

Fluxus F608 and G608 portable gas and liquid flowmeters are covered by ATEX certification (EX II3G)

Fluxusr G 601 portable flowmeter has application in check metering, leak detection and troubleshooting.

Flexim's Fluxus F601 portable clamp-on flowmeter with a NEMA 4X housing