The cvolution iris slider is a thin, lightweight and stackable control module for the cvolution hand unit. Although it's primary function is to control an iris motor, it can be set to control any given scale. In stereography, the slider is widely used to control 3D rig axis such as Interaxial, Convergence, Height, Tilt or Roll. The slider features a lens limit button and a position locking thumb screw. Up to three sliders can be stacked and attached to any cvolution hand unit.