Established in 2004, STEEL INC. is a Tokyo-based design studio that specializes in making products from steel material. CLAUSTRUM is their original in-house label, which produces anything from iPhone cases, portable ashtrays, business card holders, to key cases. All items are hand made in their Ginza factory, finished meticulously by Japanese workers. Equipped on the thin stainless steel case is a fold-out flap on the back, hence its naming, which flips out to transform into a horizontal and vertical stand. Furthermore, this flap mechanism can function as a grip for holding the iPhone between two fingers, making it easier to operate the gadget with one hand.