Double-layer PCB design for stable and reliable connections - One ESP32 GPIO is wired to two pins on opposite sides of the board, reducing poor circuit contact and improving signal transmission reliability. Compatibility and scope - Only suitable for 38PIN narrow version ESP32 without mounting holes. - Not compatible with other ESP32 versions. GPIO expansion for flexible wiring - Expands a single ESP32 GPIO to two accessible pins, making it easy to reuse pins in smart home projects and serving as a convenient breadboard alternative. 2 convenient connection options - Pin Header and Screw Terminal: choose the connection type that best fits your setup and wiring style. Use scenarios - Smart home wiring: drive two devices (for example, an indicator and a relay) from one GPIO without occupying additional pins. - Prototyping and quick wiring: use on a breadboard-friendly breakout to simplify testing and project development. - Signal distribution: split a single GPIO signal to monitor or feed two circuit points simultaneously for testing or measurement.