COMPATIBILITY (IMPORTANT): Only suitable for 38PIN narrow version ESP32 without mounting holes, not suitable for other versions. GPIO 1 INTO 2: This breakout board can expand one GPIO pin of esp32 development board to two, which is convenient for users to reuse all pins in smart home projects. Nice breadboard alternative. 2 TYPE CONNECTIONS: Pin Header & Screw Terminal. Just select them according to your purpose. DOUBLE-LAYER PCB: The expansion board is a double-layer board. One pin is wired on both sides. Therefore, the circuit is stable and highly reliable, and there be no poor circuit contact and unstable signal transmission. UPDATED VERSION: Compared with the previous version, the board of this version has been soldered completely. No need to solder parts by yourself, which is very convenient to use. Material:plastic colour:Green Package Contents: 6 x ESP32 Breakout Board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.