The SN-31 SD is a replacement needle (replacement needle) that performs identical to the original needles produced by the manufacturer for use with SANSUI 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 SD.56-31 SN-31, ST-3200 WHT (4951586351306).