It is used to adjust the lens focus, zoom and iris.
Zoom
● Click 
, and the lens zooms in.
● Click 
, and the lens zooms out.
Focus
● Click 
, then the lens focuses far and the distant object gets clear.
● Click 
, then the lens focuses near and the nearby object gets clear.
PTZ Speed
Slide 
to adjust the speed of the pan/tilt movement.
Iris
● When the image is too dark, click
to enlarge the iris.
● When the image is too bright, click 
to stop down the iris.