Fangrui Product Details 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