Standard Raspberry Pi 40PIN GPIO extension header, supports Raspberry Pi series boards, Jetson Nano ^^ High quality relays, loads up to 5A 250V AC or 5A 30V DC. Photo coupling isolation, prevent interference from high voltage circuit ^^ Standard rail mount bottom case. Onboard LEDs for indicating relays status ^^ Relay control pin selection jumper, allows to control the relays by custom pins other than the default pins. Reserved control Interface, allows to work with controllers like PLC ^^ Comes with development resources, including examples in wiringPi, bcm2835, python, python-bottle (webpage control), and crontab (cron job)