Product Name: Gakken Electronic Block EX-SYSTEM EX-120 Crystals from battery leakage are present on the electrode part inside the battery box (see photo). Purchased 50 years ago, and used without problems for 3-4 years. After that, it was left unused. Around 30 years ago, I tried to operate it by inserting batteries, but it didn't work and was left as is. As a result of leaving the batteries inserted, it leaked. Operation has not been confirmed. Quality cannot be guaranteed. Please consider it as junk. #ElectronicBlock #EX-SYSTEM #EX-120 #Gakken #Craft #ElectronicCircuit #ExperimentCircuit #ElectricalExperiment #Block