TA Instruments interview questions

Multi-level interviews. Hiring manager, other regional managers, sales director. Interviews were spread out. Same with other positions. About 3 interviews. They were all professional and courteous, but expect to get grilled by at least 1 interviewer

Interview was very difficult. 6 rounds. 2 rounds of HR and 4 technical rounds. Basic fundamentals of electrical and mechanical engineering. HR - questions follows star format. Why TA? Relevant experience in instrumentation.