This is a SHARP pocket computer, likely manufactured around 1990. It can be used for learning BASIC programming, as well as a scientific calculator. This item has been internally cleaned and upgraded with 128KB of internal RAM. I have confirmed that it can perform basic calculations and program creation, with no issues in calculation or display, but the "0" key is slightly unresponsive. I have not been able to check all functions, so there may be other issues. The exterior has fine scratches, dirt, paint peeling, and overall yellowing. Also, the body cover is from another model (PC-E500PJ) and has a different color. Furthermore, the RAM card slot cover is missing. Please check the photos for details on the condition. ・About the 128KB RAM CARD This item includes a self-made RAM CARD. Programs can be backed up independently using the internal battery. I have confirmed that the PC-E500 recognizes 128KB, but it seems that it cannot be used in conjunction with the main unit's RAM.