They differ in number of filaments nominal power and base type.
Xenon bulb base types.
As the human eye has evolved to see in daylight xenon lighting causes less eye strain than other bulb types making it a more convenient and safer night lighting option.
Xenon bulbs increase reflections on road signs and markings.
A measurement of 8 millimeters means you have a g8 base xenon bulb which only comes in 120 volts.
If your bi pin bulb measures 4 millimeters between pins you have a g4 base bulb which comes in 6 12 or 24 volts.
If your measurement is just a hair wider than 6 millimeters you have a bulb with a g6 35 base which comes in 12 24 or 120 volts.
Screw bases 10mm miniature screw e10 11mm miniature candelabra e11 12mm candelabra e12 14mm european e14 17mm intermediate e17 26mm medium e26 26mm medium skirted 27mm european medium e27 39mm mogul e39 fluorescent pin bases miniature bipin medium bipin single pin recessed double contact 4 pin single ended 4 pin 2gx 13 axial twist lock bases.
Also known as dual filament bulbs these are used to power both the main and dipped beam of your headlights.
Bulb type trade number cap base filaments nominal power 12 8v high low beam where applicable comments image hb1 9004 p29t 2 65 45 w hb2 9003 p43t 38 2 60 55 w european h4 w stricter geometric tolerances lower max output limit hb3 9005 p20d 90 1 65 w hb3a 9005xs p20d straight 1 65 w hb3 w 180 straight base hb4 9006 p22d 90 1 55 w.
H1 h3 h4 h l h7 h8 h9 h10 h11 h13 h l h15 h16 psx24 5202 psx26 p13 9012 hb1 9004 hb3 9005 hb4 9006 hb5 9007 881 882.
Despite their similarities each of these bulb types is slightly different.