These fit all Headlamp Headlight Wiring Relay Kit. Adds relays to most older British cars that use 2 headlights. Relays increase the amount of power that makes it to the lights increasing brightness. They also greatly reduce the amount of current going through the switch thus increasing switch life. These fit all TR3 TR3A TR3B TR4 TR4A TR250 TR6, Spitfire, MGA, MGB, MGC, MG Midget, MG TD and TF, Austin Healey 100-4, 100-6, 300, and 3000 and Sprites. Includes Instructions.