This is an original MGB RVC-type tachometer. It is in excellent condition, and worked when I last tested it several years ago, but I have no way of testing it now as I no longer have the car it was to be used in. These speedometers were used in MGB's, MG Midgets, and several other British cars. I believe it still works properly, but since I can't say for certain, it's offered at a bargain-basement price, and without a warranty. Tach is designed for 4-cylinder cars with 12 volt negative ground electrical systems.