Abstract: A system for interlocking together two panel members comprises a washer member having first and second washer portions connected by a necked down portion and having a through bore for receiving a fastener. The washer member is fastened to a side of a first panel member. A keyhole slot is formed in a second panel member, the slot having a relatively large opening portion leading to a relatively narrow opening portion. An aperture is formed in the second panel member spaced from the keyhole slot to define a bridge portion between the aperture and slot. A clip member attaches with a snap fit to the bridge portion and spans the keyhole slot terminating in an abutment portion at its distal end. When the two panels are interconnected, the necked down portion of the washer member is positioned within the narrow portion of the keyhole slot with the abutment portion of the clip retaining the washer therein.