40 Pin universal Adapter is a piece of hardware which helps you to connect various development boards/ breakout board/ modules to you breadboard w/o covering the other pins and w/o any wires. Various board such as Arduino Nano/pro mini/pro micro, STM32 Bluepill/black pill, some teensy board, Silicon labs thunderboard, ESP32 Board, ESP8266 Board, ESP01 (which is not breadboard friendly), Rpi pico and not only this but also you can connect Rpi 3/ 4/zero/zero W/ Zero W2.