SEALED BEAMS PAR are used in outside lighting, the number beside PAR is a measurement that describes the diameter of the PAR lamp or bulb. To figure out the diameter, divide the number next to PAR by eight. For exemple PAR 36 = 36/8= 4.5รถ diameter. PAR38 Light bulb has diameter of 4.75 Inches. If you have a sealed beam of 5-1/2 diameter you have to look for a 5.5x8 = PAR44. Beam spreads are designated as FL (flood), SP (spot).
