improved connectors of the type used for attaching shelves and bins to slot boards are generally shaped like the known w - clips and z - clips but have ribbed channels to receive one edge portion of a shelf or bin . the edge portions of the shelves and bins are shaped to fit within the channels and grooved to fit around the ribs on the connectors when a connector is attached to a shelf or bin by seating the corresponding edge portion of the shelf or bin in the channel of the connector and seating the rib on the connector in the groove in the shelf or bin to mechanically interlock the connector with its shelf or bin . a combination connector is also provided which can be used either as a w - clip or a z - clip .