The STY-20 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.50-20SG STY-20SG RED (4951586390909).