Features: 100% brand new and high quality Can be inserted directly into mega2560 due,Ideal for linking up to your Mini Mega2560 Breadboard for raspberry pi banana pi etc,or others MCU PLD CPU ( AVR STM32 ARM PIC C51 NRF24LE1 CC2530 MSP430 STM8 FPGA CPLD etc.) 4-button Common Cathode key module(When pressed output low level). GND K1 K2 K3 K4" 4 PIN OUT 2.54mm Adopted of high quality electronic components, and accuracy process, ensure for the durability Specification: Working voltage: DC 0-48V GND K1 K2 K3 K4" 4 PIN OUT 2.54mm Size:12.7*33mm/0.5*1.3in Weight: Approx.3g/0.1oz Package list: 1 x 4 Button Key Module