It was a 3 step process: initial phone screening that lasted about 20 minutes, a second phone interview that lasted about an hour, then a 4 hour in person interview. The first phone conversation was forgettable, I think it was to schedule the second interview and confirm that you can speak coherently over the phone. The second phone interview was standard interview questions. Being able to demonstrate knowledge of the company and answer questions about yourself that show desirable traits. The in person interview is a tour of the facility, about an hour long interview with two managers, then a written test.