Three on one interview. They will have your future supervisor, one may be upper management, and the other a shop lead. They try to through you off your game and fluster you. Ask you a few questions identify the issue and how you'd solve it. They keep it very professional it will throw in some humorous things to see how you react. I keep things lighthearted and interesting as well as fun. But nevertheless it is a serious and professional interview. They give you two options for dress code formal and business casual, I prefer to do formal always take the highest option available.