SONOFF 4CHR3 & 4CHPROR3 are both 4-gang Wi-Fi Smart Switches designed to give you the ability to integrate smart control into your existing home to enable a smart home. Each smart switch has 4 gangs that can be used to control lights and other home appliances at the same time in four areas of your home. There is a major difference between 4CHR3 and 4CHPROR3, which is 4CHPROR3 is designed with an additional function for RF control. The function is purposely adopted to make you turn on/off the device connected with 4CHPROR3 via theRM433 remote controller. The new improvement on 4CHR3 and 4CHPROR3 compared with 4CHPR2 and 4CHPROR2 is for users to set these 3 working modes on eWeLink APP instead of the hardware itself, easier to operate. So you can enable self-locking mode to turn on/off 4 connected devices separately, interlock mode to turn on 1 connected device every time and turn off the rest of devices simultaneously and inching mode to turn on 1 connected device and then make it turn off automatically after a given time (0.5 - 3600s). For the device away from the switch, you can create a moveable space in virtue of a DIN rail to make them be connected. Simply activate devices through your voice when the switch works with Alexa and Google Home smart assistant. Package SONOFF 4CHR3 or SONOFF 4CHPROR3 *1 SONOFF 4CHR3 or SONOFF 4CHPROR3 User Manual *1