Glossary of Terms

AUTO SELECT™ – Auto Select is Peterson’s trademark name for a selected group of imported automotive products. Unlike other imported products, Auto Select are designed, built and quality-inspected to PM’s stringent standards.
ASAE – American Society of Agricultural Engineers. Defines industry standards for agricultural equipment, including ASAE S279.17, Lighting & Marking of Agricultural Equipment on Highways.
BLADELIGHTS® – Peterson’s trademark name for snowplow and emergency lights.
BULBS – A glass capsule containing electrodes or a filament, which glows when connected to an electrical source. Three bulb types are generally used for illumination and vehicle safety lighting:

  • Incandescent – there are two basic incandescent bulb styles most frequently used in general lighting products. An incandescent bulb is rated by the number of hours it will burn under ideal laboratory conditions. Peterson uses 15,000 hour-rated bulbs whenever possible to achieve maximum performance.
  • Bayonet Base – a traditional, widely used metal-based bulb such as 1156, 1157 or 1895.
  • Wedge Base – a non-indexed, baseless, all-glass bulb such as 3056, 3157 or 193.
  • Halogen – commonly known for bright, intense light from a small package. In halogen bulbs, tungsten particles from the filament are continually redeposited back on the filament to extend its life. Halogens are available in H1, H3 bulb and sealed beam configurations.
  • Xenon – a bulb type commonly used in emergency warning lights. Xenon refers to the gas sealed inside the bulb. It serves as a starter in order to accelerate the start-up process of high-intensity discharge headlights.


CANDELA – A standard unit measuring the amount of visible light emitted by a light source in one direction.
CANDELA-SECOND – A standard unit measuring the amount of light seen through a clear lens during one second.
DOT – US Department of Transportation; a cabinet-level Federal department which governs transportation systems in the United States. See also: FMVSS 108, NHTSA
DRIVING LIGHT – A front-mounted white light which produces a long-range, pencil-shaped light pattern. Improves nighttime visibility at highway speeds. See illustration of fog and driving light beam pattern page. See also: FOG LIGHT
FMVSS 108 – Federal Motor Vehicle Safety Standard No. 108; Part of the Department of Transportation’s uniform safety standards for new vehicles and vehicle components. FMVSS 108 regulates head lamps, tail lamps, stop lamps, reflectors, marker lamps, turn signals, ID lamps, etc. Peterson products exceed this regulation. See also: DOT, NHTSA
FOG LIGHT – A front-mounted lamp which produces a low, wide beam pattern in front of the vehicle to greatly increase short-range visibility. Ideal for added driving safety in rain, snow or fog. See also: DRIVING LIGHT
FRESNEL LENS – A compound-angle refracting lens divided into prismatic sections. Designed to collect light and concentrate output in a specific direction. See also: LENS
GREAT WHITE® – Peterson’s trademark name for our white light-emitting diodes. See also: LED
HARDWIRED – A term for permanently attaching lead wires to a lamp assembly, rather than using a detachable terminal plug. Hardwired lamps are better sealed and have fewer connection points for greater durability and better corrosion resistance.
LED (LIGHT-EMITTING DIODE) – A small, solid-state electronic light source. Some advantages of LED-based lamps are:

  • Up to 100,000-hour rated life
  • Solid state—Vibration resistant, with no filament to break
  • Low amp draw—90% less than standard bulbs
  • Faster response time for added safety
  • Maintenance free
LENS – A transparent or translucent cover over a bulb or LED. In accordance with FMVSS 108, Peterson manufactures lenses with two thermal plastic resins:

  • Acrylic – the most widely used material for lenses. Features moderate heat and impact-resistance.
  • Polycarbonate – a premium material with higher impact and heat resistance than acrylic.


LUMEN – A standard unit measuring the flux emitted by a light source in a solid angle of 1 steradian by a point source having a uniform intensity of 1 candela. Measured lumens is the flux emitted by a complete lighting assembly as observed in a lab. Calculated lumens for an LED light assembly is derived by multiplying the flux of a single diode by the total number of diodes contained in the assembly.
LUMINOUS FLUX – The perceived power or visual intensity of a light source.
JOULE – A standard unit measuring energy generated by an electrical circuit. For a strobe circuit, the figure may refer to the energy of a single flash or to a succession of rapid flashes. See also: WARNING BEACON
MAXI-SEAL® – Peterson’s trademark name for our exclusive collection of wire harness technologies.
MIRRORS – Peterson offers a complete line of passenger car, light truck and van, and heavy duty mirrors and assemblies.

  • Convex – also known as “blind spot” mirrors. Features a fisheye design permitting a wider view angle than a traditional mirror.
  • Elliptical – features a protruding, half-moon shape that allows the driver to view a 180° area with a minimum of distortion.
  • Wedge Base Convex – an improved version of the traditional convex. Allows over 50° increase in viewing area with less distortion.
  • West Coast – A style of rear-view mirror assembly designed for large trucks characterized by a tall, narrow mirror face and two or three mounting arms that attach to the door above and below the window opening.
MOUNTING CONFIGURATIONS – Peterson offers many mounting options for our vehicle lights The three most common are:

  • Flush mount – a metal or rigid plastic bracket locates the light behind or within a pre-cut mounting hole so that the light does not protrude appreciably beyond the mounting surface.
  • Grommet mount – a rubber or flexible plastic collar push-fits between the light assembly and a pre-cut mounting hole of specific size and shape. Provides some vibration isolation. Often allows lamp removal without tools.
  • Surface mount – light is attached above the surface of the vehicle. Usually prevents the need for creating large holes in the material, but it may require small holes for routing wires and attachment hardware such as screws, bolts, or rivets. Light assembly may mount directly to the vehicle, or may use a separate mounting bracket.
NHTSA – National Highway Transportation Safety Administration; A part of the Department of Transportation, this Federal agency oversees and regulates many aspects of vehicle construction and highway travel. See also: DOT, FMVSS 108
NIGHTWATCHER® – Nightwatcher® is Peterson’s trademark name for the entire line of high quality fog and driving lights, off-road lights including LED bar light retail series, and related accessories.
PAR36 – An industry standard size and shape for directional sealed beams. Does not designate voltage, brightness or beam pattern.
PHOTOMETRIC – Photometry is the calculation and measurement of quantities of light, such as luminous intensity. This is usually measured in candela or candle power.
PIRANHA® – Peterson’s trademark name for our premium LED lights with a higher number of didoes for a distinctive multi-diode lens look. Piranha® lights not only use state-of-the-art LED circuitry, but are designed and manufactured to be unsurpassed in optical performance and durability while exceeding all applicable regulations and standards.
REFLEX – The characteristic of efficiently reflecting light directly back towards its source regardless of the source’s location. Also, a surface or component having this characteristic.
SAE – Society of Automotive Engineers; A non-governmental body which establishes standards for the automotive industry.
SPITFIRE® – Peterson’s trademark name for our exclusive microprismatic, wide angle reflectors. 47,000 microprisms per square inch provide superior candle power compared to conventional reflectors.
SUBMERSIBLE – A submersible light allows water into the unit when submerged. The bulb and socket are protected by an air pocket formed by the bell jar principle, which permits only a certain amount of water to enter by capturing a pocket of air within the lens assembly, preventing water from contacting the bulb.
VIBAR® and VIBAR II® (VIBRATION IMPACT BARRIER) – Developed in the 1960’s, Peterson’s Vibar® was the first real shock-mounted socket in the industry and eventually became the standard. This exclusive, resilient socket absorbs road shock and vibration for longer bulb life.
WARNING BEACON – There are three basic types of warning beacons:

  • Flashing – an emergency lamp which provides intermittent power to a stationary bulb, causing it to flash or blink on and off.
  • Revolving – revolving lights are available in several variations:
  • 2-Beam – an emergency lamp with two sealed beams or light bulbs which rotate to produce a full, 360° warning.
  • 4-Beam – an emergency lamp with four bulbs. Compared to a similar 2-beam unit, produces twice the light output and twice as many flashes for a given rotation speed.
  • Rotating Reflector – features a stationary light source with a revolving reflector to produce the 360° warning. This design is commonly used in light bars and compact units.
  • Strobe – lamp which energizes a gas-filled glass tube to produce, quick, extremely bright flashes.
  • Dual Flash/Quad Flash – a unit which flashes one strobe light head several times in quick succession before a longer pause. If the system is equipped with multiple strobe heads,
  • each head flashes multiple times in turn.
  • Master/Slave Units – the master unit has a built-in control circuit, will operate independently by itself and can operate a slave unit. The slave unit has no built-in control circuit and requires the master unit to operate.


WATT-SECOND – A standard unit measuring the amount of the electrical current delivered per second.
WELDING – Fusing plastic components together by quickly generating friction heat to momentarily melt the mating surface and create a strong, hermetically sealed bond. Peterson uses three distinct plastic welding techniques:

  • Linear—vibrating one part against another in a single direction.
  • Sonic—subjecting the assembly to high-frequency sound waves which vibrate the seams of the plastic.
  • Spin—rotating one component against another at high speed to create a circular bonding surface
VIZ PACK – Peterson’s term for a variety of retail-friendly, transparent package designs, including clamshells, blister packs, and bags. All Viz Packs are clearly labeled with part number and description, are pilfer-resistant and tamper-evident, and nearly all are hangable.

Have questions about our products?

Contact an expert today.