Chromed aluminum. Fits Evo, Twin Cam and M8 Big Twin models with head vents. Comes with two pairs of, 1/2-13 and 3/8-16 threaded, banjo bolts to cover both Evo (1/2-13) & Twin Cam/M8 (3/8-16) applications. Used in combination with aftermarket air cleaner assemblies. Note: with 93-up type long banjo bolts.