Trackball Roller Plus
This one is beautiful.

Ball diameter: 63.5 mm [see Trackball Ball Sizes and Replacement]

The blue button on right button, is a drag lock. (equivalent to holding the left button)
The button north of the trackball is X-Y switch. “ Pressing this switch once gives left-right cursor movements only, pressing again gives up-down only. To cancel this function the switch should be pressed a third time. Selection of this function is indicated by an LED at the top left of the unit.”
The brown translucent cover is removable. The purpose of the cover is to prevent accidental clicks.
Seems these trackballs are designed for wheelchair.
The lower left button, with picture of man running, is speed control button. Basically, a DPI switch.

How much? I found $280 online, while another site is $400+. You'll have to search.
Manufacture home page at http://www.traxsys.com/AssistiveTechnology/Trackballs/RollerPlusTrackball/tabid/1418/Default.aspx

Size
- Length: 21.5 cm
- Width: 13.4 cm
- Height: 6.7 cm
- Pressure: Buttons require only 64 g of pressure


Traxsys Trackball Roller II
