1MB (8Mbit) Flash size.
AP, STA, AP+STA modes available.
Very simple AT commands, easy to use.
Low-power consumption and small
Internal LWIP interface.
Only four pins interface, VCC-3V3, GND, TXD and RXD.
AT commands firmware. New IC ESP8266ex
This module just have small upgradation on ESP-01 PCB board
5 x ESP-01S Wireless Module
5Pcs ESP8266 ESP-01S Remote Serial Port WIFI Transceiver Wireless Module