Profile or fixed beam-angle spotlights have constant beam widths, meaning you cannot make their beams or frames of projected light larger or smaller unless you physically move them. However, you can focus their lenses, allowing you to create softer or harder beam edges. Stage productions commonly make use of profile spotlights by fixing gobos (or partial screens) over them in order to project different shapes.
A slight variation on the profile spotlight is the zoom profile spotlight, which uses a pair of adjustable lenses to broaden or narrow beam width.
Fresnel spotlights are named for fresnel lenses, which are comprised of a series of concentric rings that help converge light on to a particular spot. Unlike profile spotlights, which can be positioned at a distance, you should keep fresnel spotlights close to the area you want illuminated, such as the stage, for optimal results. The convex side of the fresnel lens typically has angles cut into it, which helps to soften the light being projected.
The initials "PC" refer to three different varieties of spotlight lenses: piano convex, prism convex and pebble convex. The piano convex lens is the oldest, and it is completely clear, which gives its beams a very hard edge. The alternatives, prism and pebble convex lenses produce soft-edged beams because they use angled and pebbled (or bumpy) surfaces, respectively, to diffuse light.
Hunters, campers and landscapers are just a few examples of individuals who use cordless spotlights. Whether they are targeting animals, illuminating picnic tables or highlighting lawn decorations, the lights offer a degree of mobility well beyond the capabilities of standard (and usually bulkier) plug-in spotlights.
There are two main varieties of cordless spotlights: those powered by disposable batteries and those powered by rechargeable batteries. While the former provide weaker beams and typically burn out their batteries after four of five hours of use, the latter are brighter, and you can recharge their batteries quickly.