This was found while cleaning out my parents' house. As a child interested in transistor radios (around 1968), I learned the shapes and types of resistors and capacitors with this. In particular, the included circuit collection has 30 circuit diagrams that can be easily assembled, and it's still interesting even now. I am selling this as-is because I cannot confirm whether all the parts are present or if they function correctly. ・For more details, please see the "Electronic Block Research Museum". http://yukikaze.fan.coocan.jp/denshi-block/products/02_SR/01-SR-1A-2A.html