Stop Brake/Tail Lamp (With License Plate Light) Round Style as used on early bobbers. Two wire hook-up means the light is self grounding(wiring not included with light). Light features standard automotive style bulbs (#67 miniature). Replacement bulbs are easily sourced from local autoparts stores should you ever require. Dimensions: 2.75" Diameter, 1.75" Thick, 1.5" Bolt Spacing.