Doublelayer PCB design for reliability and stability: The expansion board uses a twosided wiring approach, with one pin connected on both sides. This construction helps prevent poor contact and unstable signal transmission, improving overall circuit stability. Compatibility you can trust: Designed specifically for the 38PIN narrow version ESP32 without mounting holes. Not compatible with other ESP32 versions. Flexible connection options: Two types of connections are available—Pin Header or Screw Terminal. Choose the connection method that fits your project needs. GPIO expansion from one to two: This breakout board allows one ESP32 GPIO pin to be expanded into two pins, making it convenient to reuse all pins in smart home and other projects. It serves as a practical breadboard alternative. Practical use scenarios: Smart home projects: Use the doubled GPIO to drive a relay and an indicator (LED or LED strip) from a single GPIO, simplifying wiring and control logic. Prototyping and testing: Connect to a breadboard via the Pin Header or Screw Terminal for quick experimentation and signal routing without soldering. Spacelimited or multipin workflows: Expand a single GPIO to two outputs to support simultaneous control of multiple peripherals while keeping the layout neat and organized.