It is clear to me that naming any business partners of the current employer can get me into legal trouble or at least mark me as a big unreliable mouth in a job application or interview.
I would like to apply to an OEM now, which my current employer contracted as a second level supplier. So I have worked full time in a big project of the OEM around a year and a half. I know their technology, tools and how their business run. I have a unique advantage. But how should I state it in my resume and cover letter and in the interview.