Designed to improve cooling for extended regulator life. Reflects engine and exhaust heat, and is grooved to interlock with the regulator. Machined from die cast alloy, contains 20% more finned area than stock regulator Fits most stock regulators seen on 1970 - 1999 models. Fits: FL 1970-1984, FX 1971-1984, XL 1978-1984, FXST 1984-1988, FLST 1986-1988, FXR 1982-1988, FLT 1979-1988.