Abstract: An expandable jack that is stackable, is provided with four base members having vertical columns extending upwardly therefrom. A horizontal cross-member structure, having width adjustment capability, is adapted to slide along the height of a pair of vertical columns and once appropriately height positioned to be locked into place. One of the cross-members of the cross-member structure has height adjustment capability. The device permits quick and easy height or width adjustment and also permits quick and easy height adjustment of one or two horizontal cross-members.