Houdini keyboard Arm is ideal for the Roller Mouse Pro usage. 18 Deep Glide Track(top - arm only). Position indicators for both height and tilt. Soft-touch wheel allows convenient, stable, one-hand tilt adjustment. The 20" thin platform is for the use with keyboard and Roller Mouse Pro OR a mini keyboard and mouse. It is NOT sufficiently wide for a keyboard (standard) and a mouse. 

Houdini offers Lift-N-Lock height adjustment, Thin-Glide track, 360° swivel 
Height Range: 3" Above to 5" below the worksurface (8 in) 
Tilt Range: -20° to +10°