Itead SONOFF 4CH R3/ PRO R3 Wifi Switch 4 Gang 4 Way Mounting WiFI Wirele Smart Switch APP Remote Interrupter Relay Switche SONOFF 4CHR3 & 4CHPROR3 are both 4-gang DIY 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 the RM433 remote controller.Actually, SONOFF has ever released two types of 4-gang smart switch (4CHR2 and 4CHPROR2.) which comes with almost same functions with 4CHR3 and 4CHPROR3. But all the above units are still different in 3 working modes including self-locking, interlock and inching mode. 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 aistant. Quick to Acce 3 Working Mode Compared with 4CH ProR2, you can acce self-locking, interlock and inching mode on APP directly. Run 4 Devices Sparately - Self-locking Mode Allow you to turn on or off 4 connected lights independently Automate More Devices- Interlock Mode One channel controls one work status, enable interlock to turn on 1 channel and turn off other channel simultaneously. Keeps On for A While, Then Turns Off Automatically -Inching Mode Don't Want to stiffly fumble in the dark for the way? Enable inching mode to set a "on" schedule for your corridor light, and it will automatically turn off after reaching the preset time Voice Controls Your Home Compatible with Alexa and Google Home.Wanna turn off the light immediately? Just tell it to do. Easy to Out-of-Reach Device Mounted on the guide rail, convenient to connect and control devices far from the switch Security Comes Before Everything The durable flame-retardant PC shell provides the maximum safety for connected devices in use.