From the manufacturer

Quick-Connect Keyboard Tray

Ready to use out of the box. No tools needed. The keyboard tray slides into the receiver which clamps down to secure it to the riser

Optional Dual Monitor Arm

The D1D-E monitor arm holds two 30" monitors weighing up to 22 lbs. each. The D1D-E is not included with the riser so be sure to order it separately

Perfect for Two Large Displays

Keyboard tray can also be used with a laptop. 

The cutout on the platform provides room to tilt your laptop screen back. This will give you an additional screen without blocking view of the monitor.

Platform Raises Straight Up

Minimum height 4.7"
Maximum height 19.7"
Dimensions of Riser Platform and Keyboard Tray
M7-E-40B
M7-E-40B
M7-E-40B
M7-E-40B