SPECIFICATIONS-Traditional Incandescent Lighting Illuminates Around the Perimeter of the Dial-Works With Most Pre-1989 (Pre-1987 Mustang) Ford & Most Chrysler-12 & 16 Volt Compatible, Well-Suited With Nearly Every Street or Race Car Electrical System-Gauge Kit Includes Bulb & Socket Assembly, Red & Green Bulb Covers, Mounting Hardware & Detailed Instructions for Installation-Autometer's Race Proven Air-Core Electric Instruments Provide Quick & Accurate Readings-Bulb & Socket: 3220-Light Covers: Red 3214 & Green 3215-Mounting Hardware: 2230-Size: 2-1/16" (52.4mm)-Type: Air-Core-Range: 73 Empty / 10 Full (NON-LINEAR)-Lighting: Incandescent