DollaTek 5Pcs ESP8266 ESP 01S WiFi Serial Transceiver Module with 1MB Flash for Arduino

Latest version esp-01s,comparing to ESP-01, ESP-01S will provide you stronger antenna singna 1MB Flash Memory. upgraded from 512KB Integrated WEP, TKIP, AES, and WAPI engines. 802.11 b/g/n Wake up and transmit packets in 2ms. Standby power consumption of 1.0mW (DTIM3) Document link: https://nurdspace.nl/ESP8266