However, since acronyms like NFDM are most often pronounced as separate letters, is the safer and more standard choice.
If NFDM is read as a single word or brand name (e.g., "Nifdim"), use : NFDM-225 z R--
The number "225" reappears across Tg, kV/mm rating, and type designation – a clear indication of deliberate parametric matching. However, since acronyms like NFDM are most often
It is important to clarify upfront that does not correspond to any known, widely recognized standard industrial code, commercial product designation, or scientific nomenclature (such as a chemical catalog number, a military specification, or a technical drawing revision) as of the latest available data. If a component labeled NFDM-225 z R-- fails
If a component labeled NFDM-225 z R-- fails in service:
The phrase appears to be a technical or model designation, likely from a Polish-language context (given the use of "z" meaning "from" or "with"). The proper article in English depends on how you read the acronym NFDM.