The Siemens 7ME3960-0SM20 is a mounting strap for dedicated transducers on the SITRANS FS220 ultrasonic flowmeter, sized for pipe diameters DN300 to DN600 (Leg. Nr. 1012MS-2). This is the hardware that secures the transducer pair to the pipe — without it, the flowmeter can't be installed. If you're maintaining or commissioning an FS220 installation in that pipe range, this strap is the specific part number to order.
This part is not RoHS-compliant, which matters if your site or end customer requires RoHS conformity for all components. REACH Article 33 candidate-list information is available on request. Export control is straightforward: AL: N / ECCN: EAR99I, so no special licensing for most destinations.