Sonoff REV Relay Module has the following specifications

Nano Size

Dry Contact Output

Low Power Supply – 5VDC low voltage input

LAN Control – Turn on/off the device even when WiFi has no Internet access

App Support – Free iOS and Android mobile App eWeLink

Remote ON/OFF–Turn electrical devices on/off from anywhere

Sync Status–Real-time device status provided to App

Timing–Set scheduled/countdown timers to turn on/off at specified time

Share Control– Control your smart home together with your family

Scene–Turn on/off a gang of devices with one tap

Smart Scene–Triggered on/off by temp, hum or other environmental conditions from sensor

Compatibility –Works perfectly with Amazon Alexa, Google Assistant, IFTTT, Google Nest

Long story in short, it’s a 5V wifi inching/selflock relay module by SONOFF.

Just like a standard SONOFF switch, you can use it to work with eWelink app, Amazon Alexa, Google Home, IFTTT..etc.

The 5VDC input, nano size and dry-contact output makes it different from traditional SONOFF product, this product is a wireless switch supports inching /self-locking mode. Users can add the device to the APP eWeLink in order to remotely control connected home appliances or devices. In self-locking mode, customers can remotely turn on/off connected devices immediately. When in inching mode, customers can have two wiring ways to select:

• Turn on 1s and then auto-off
• Turn off 1s and then auto-on.

Reference

Similar devices to the Sonoff REV Relay Module:

Sonoff Slampher Smart Lamp
Sonoff S26 Smart Plug