Followspots for manual tracking of performers on stage or groups.
They have a double lens with zoom optics for continuous adjustment of the beam and the edge sharpness.
The iris, a circular, adjustable screen allows to quickly change the size of the circle of light.
Some have built-in color changer follow spots, other models can be fitted with color filters or color changing magazines.
Affordable enforcement officers use halogen lamps, the pursuers are better with HMI or MSR lamps equipped for higher light output and less hot housing.