Up for sell is Seller Hand made Remote Control Kit Wireless Remote Control Sensor is full metal(hand made) Wireless Remote Control is not SONY original,it is Replacement. For SONY Discman D-10 D-100 D-88 D-15 D-150 D-25 D-25s D-250 D-555 D-z555 D-77 D-55 D-303 D-9 D-90 Please note that it can only be used when the CD uses a 9 volt power supply, which is the same as the original Sony RM-DM1K/DM5K. It cannot be used when the CD is using a battery. This is the design of Sony DISCMAN, not a remote control issue. The function of the remote control is the same as the original Sony RM-DM1K/DM5K.