Do not buy. Just don't. Or, at least, do not buy from this seller. Seller won't send you driver and application, and won't respond to messages. You need to open a dispute, and then, at the last possible time, he'll send you a link to the software. You may also receive a device without WiFi module, and it will be extremely hard to prove device doesn't have a WiFi, especially since seller doesn't provide any software to use the WiFi, nor instructions of any kind about using device through WiFi. I bought probably more than 200 items here, but experience with this seller is the worst so far.
Okay, so I figured out my item actually does contain WiFi module. One needs to press and hold the button for 5 seconds (the light shall start 3-blinking), release button, then press and hold button again for 5 seconds (the light shall start blinking rapidly). New wifi network will appear (2.4GHz), I figured the password is 12345678. The trouble is, the eWeLink app which supposed to control the device, doesn't connect at all. So it's all moot, and you won't be able to use WiFi at all. In the end there's always option building such device yourself, may be with attiny85 and esp8266.
ordered and payed with WIFI. received WITHOUT wifi.
ordered with wifi and received without wifi