Sonoff smart switches provide you with perfect intelligence control solutions for your home or workplace. By using the free eWelink App wireless control, Sonoff can make your life easier. Everything is under your control! Control your home appliances or electrical devices anytime and anywhere Wherever you are, and whenever you want to turn ON/OFF your home appliances or electrical devices, you don't need to be there or others' help, you just need slightly touch the ON/OFF button on the Ewelink app. The connected devices will be automatically on/off immediately. Remote control 4 devices & 3 working modes Sonoff 4CH Pro can connect four household appliances or electrical devices, so you can remotely control four devices ON/OFF at the same time or separately. There are three working modes for your different needs: self-locking mode, interlock mode, and inching mode. Self-locking mode: Turn on/off 4 connected devices separately Interlock mode: Turn on one device every time, and turn off others at the same time. Inching mode: Turn on the connected devices just for 1-16s (the time is adjustable). Self-locking mode + Inching mode: Some devices in self-locking mode, while the others in inching mode. Note: the RF Remote is not included, please order separately Set timing schedule Sonoff smart switches enable you to set timing schedules for your home appliances or electrical devices. To do this, you just need to set the single/repeat/countdown timers on the Ewelink app, then you can schedule the connected light to turn on at 6:00 pm everyday, or schedule the fan to launch at a specified time so that the house can keep cool before you arrive home. Advanced voice control Sonoff smart switch can work perfectly with Alexa-enabled devices like Echo/Tap/Dot, as well as Google home. Just with a simply voice command, Alexa or Google Assistant will work for you, turning on/off the connected devices at once.