The STY-123 SD is an alternative needle (replacement needle) that performs as the original needle, which is not the manufacturer made for use with SHARP (Optonica) record cartridges. This replacement needle is a "synthetic diamond needle" type. This is a generic model that plays a regular range of sound ranges, with a standard conical shape. General life is about 200 hours. The successor to the SP.50-123a STY-123 YEL (4951586392408).