Abstract: An adjustable divider for a shelf or a drawer of a file cabinet is formed entirely of a spring wire. One end of the spring wire is configured as an engagement portion which has a longitudinal portion for engaging within an acute angle between a first wall portion and a bottom surface of a notch in a horizontal base which supports files, books, or any other items to be maintained in an upright orientation. A second wall portion of the notch is substantially orthogonal to the bottom surface of the notch and maintains the longitudinal portion in resilient compression against the first wall portion of the notch.