This is a black pickguard of the SSH type, a smaller "Dinky" size than a standard Stratocaster. There's a sticker on the back that says "STS." Could this be a Fender Japan short-scale Stratocaster? It's easier to understand if you look at the photos comparing it to a standard one. It has 8 screw holes, 2 control holes, and the center pickup mounting hole is not present. It's quite a mystery. There are some scratches. Some adjustment or modification may be required for installation. Thank you for looking.