Type connections: Pin header and screw terminal. Choose the one that suits your goal. Compatibility: Only suitable for narrow version 38-pin ESP32 boards. Not compatible with other versions. Double-layer PCB: Two-layer board with side-wired traces. Provides a stable circuit, reliable contacts, and consistent signal transmission. GPIO extension: Extends ESP32 GPIO pins (for example GPIO 1 and GPIO 2) to a convenient breakout, making it easy to reuse all pins in smart projects. Clean, orderly layout. Use cases: - Prototyping ESP32 projects on a breadboard or perfboard, using either screw terminals or header pins for convenient connections. - Smart home controllers or IoT devices that require easy access to multiple GPIOs for sensors, relays, and indicators. - Educational projects and hobby tinkering to learn GPIO wiring and ESP32 interfacing. This description reflects the original product specifications and functions in a clear, professional tone.