Get ready to transform your office, supply closet, warehouse or any other area with our magnetic data card holders. Simply write on the pre cut card, slip it in the holder and place on any metal shelf to keep your spaces organized. Each holder includes a 3″ high pre-cut card and you can cut replacement cards out of thin card stock. The overall width is 3.15″ with a 3″ card opening. The c-channel magnetic data card holders do not slide around and can move from shelf to shelf. If you need a variety size of shelf sizes, check out our 3″ c-channel data card holder rolls.