voltage regulator

does any one no of a company that handles a usa made voltage regulator ..... so far an none of them work all made lets just call it some where else ....went out back to my old yellow trk that been there for 10 years took one off it charging sys works fine but dont trust it cause all that jell coat is not there any more ....dont say napa bought all they had an returned them or advance or auto zone .....