What are the differences between these adjustable height desk models?
All of the full size Kangaroo models hold your keyboard and mouse on the 28 x 24 work surface with the same 16.5 inch vertical adjustment, but they also have an additional 6.5 inch separate adjustment for your laptop or monitor which is held either by a shelf as on "The Kangaroo" or on one VESA mount as on "The Kangaroo Pro". The Junior units have a smaller work surface, a lower weight tolerance, and cannot be upgraded. The mount of the Pro Junior can only tilt whereas the mount on the full sized Pro can pan, tilt, and rotate.
The Dual Kangaroo has two shelves for your monitors whereas the Kangaroo Elite(2 monitors), and Tri-Elite(3 monitors) hold your monitors on a VESA mount that can pan, tilt, rotate, and slide horizontally on its crossbar, placing the monitors as close together or farther apart as needed.
The Wallaby units only provide one adjustment in the work surface and do not have the separate adjustment of the monitor mount(Pro) or shelf(Kangaroo).
The Electric units have additional vertical travel at 20.5"(usually for taller users) and also include the same separate monitor adjustment of 6.5". They operate vertically by just the press of a button located in the front left corner of the work surface.