The block off plate is CNC machined out of a single piece of 6061 Aluminum, finished in a black or red anodized coating that protects it from salt water. For all Yamaha Supercharged GP 1800, FZ SHO, FZ SVHO, FX SHO, FX SVHO. The purpose of the block off plate is to cover/seal the exposed case whenever the supercharger has been removed. Made in china .