Universal button 4 keyboard switch module 1. Brand new and high quality.2. Can be inserted directly into mega2560 reason, perfect for connecting with Banana Pi Mini Mega2560 etc. or other MCU PLD CPU ( AVR STM32 ARM PIC C51 NRF24LE1 CC2530 MSP430 STM8 FPGA CPLD etc.)3. 4-button key module common cathode (press output low level).4. GND K1 K2 K3 K4.5. Adopted high-quality electronic components and accuracy process, ensure durability. Specification: Features: Brand new and high quality Can be inserted directly into mega2560 reason, perfect to connect with Mini Mega2560 breadboard for banana pi raspberry pi etc. or other PLD CPU MCU ( AVR STM32 ARM PIC C51 NRF24LE1 CC2530 MSP430 STM8 FPGA CPLD etc.) 4-button key module common cathode (when pressed low output). GND K1 K2 K3 K4" 4 PIN OUT 2.54mm Adopted high-quality electronic components and accuracy process, ensure durability Specification :Operating Voltage: DC 0-48VGND K1 K2 K3 K4" 4 PIN OUT 2.54mm Size: 12.7*33mm/0.5*1.3in Weight: Approx.3g/0.1oz Package List: 1x4 Button Module