The 7 1/2" lift, Model #25731, is the  is a manual desktop lift with:

• a load capacity of 15 lbs - 35 lbs.

• height range from 3 3/4"" to 11 1/4". 

• stationary base.

The 16" lift the Model 25732 desktop lift shown below:

• counterbalances monitor 
  weights from 15 lbs. to 60 lbs.

• adjusts from 5" to 21" off the desk

• lifts monitors up and down without
  forward or backward movement

• rugged steel construction

• built-in finger lift on top to position monitor

• platform is 16" wide x 15" deep