Attributes . GRK-1, GRK-100C, GRK-1DC, GRK-1M, GRK-1SC, GRK-1SC-A, GRK-2, GRK-2M, GRK-2SC, GRK-2SC-A, GRK-3, GRK-3M, GRK-3SC, GRK-3SC-A, GRK-50, GRK-50A, GRK-50C, GRK-75, GRK-75A, GRK-75C, GRK-75U, GRK-75UA . Names