Low-voltage luminaires use PAR-type lamps with compact low voltage filaments. They are available in a variety of sizes, voltages, wattages and beam spreads. The typical rated lamp life of low voltage lamps is fairly long, making them extremely popular for lighting venues such as discotheques. In theatre low-voltage lamps are often used for a very narrow beams, and are also known as pinspots .

Low voltage PAR lamps, creating clear and narrow beam. Faust, The new Israeli Opera.

ACL (aircraft landing) luminaires use compact-source open-faced low voltage lamps, which produce a very tight and powerful beam, useful for long light throws. They have parabolic reflectors and come with a glass envelope, like PARs. The main disadvantage of ACLs is their extremely short lamp life. AC lighting create a distinct fan of strong and narrow light beams. Nabucco, The new Israeli Opera.

ACLs are used to create ray-like effects (usually combined with smoke which make the beams themselves visible). They are also extremely effective when a number of lamps are combined into a multi-source unit such as the popular Svoboda luminaire which emits a sheet of intense and very directional light, creating an effect known as a light curtain . Light curtains in Sicilian Vespers Metropolitan Opera New-York.

MR units are extremely small luminaires, which use MR lamps in minute parcan shaped bodies. Four bars of MR-16 cans by Kupo.

The MR lamp is an open-faced unit combining a light source and a  multi-faceted elliptical dichroic reflector. The lamps are available in various beam angles depending on the shape of the elliptical reflector. Typical MR-16 lamps.

MRs are useful in tight situations where the size of most stage luminaires precludes their use. The compact MR units can easily be concealed inside scenic units or even in large props.
MR lamps are also used most effectively in various types of striplights, providing a soft wash over limited areas.