This 8*8 dot matrix drive module is equipped with high-speed 74HC595 deserializer chip. Only 3 signal lines are needed to drive 8*8 dot matrix screen, saving your valuable I/O resources in Arduino controller to maximum extent. Specification Working voltage: DC5V Production process: FR4 double-side tinned Humanized design: cascadable application display Working temperature: 10℃-30℃ Working humidity: 10%-90% (no condensation)