Songhe ESP8266 ESP-12F WiFi Serial Module Board for Arduino, Wireless Transceiver Remote Port Network Development Board （5pcs）

Good

Great value! They flashed just fine. As another reviewer pointed out, you need to connect proper pins in order to get them into flash mode.Same pin combo worked for me (credit to G.R.).For flashing:VCC > 3.3v,EN > 3.3v,GND > GND,io15 > GND,RX > TX,TX > RX.io0 > GND (during power on to enter flash mode).After flash for regular operation:VCC > 3.3v,EN > 3.3v,GND > GND,io15 > GND

I have never had a bad one in all the ones I've bought and used.

An ESP8266 without the development board and USB port. Small and effective, but limited to 3.3V. If you are making the switch from the large unit to this, be sure to do your research as there are differences. Works great with this programmer (you may be able to get it cheaper outside of Amazon): https://www.amazon.com/Wishiot-ESP8266-Burning-Development-Programer/dp/B08BXMGVNM/

I've been Tasmotizing Tuya based 'Smart' devices for 2+ years. [Working with ESP82666, 8265 and ESP32 modules for other projects since 2018] Now with most devices using a new NON-8266 module, I have been forced to convert the devices to 8266 modules.. With the price point being low enough, it makes the conversion worthwhile. I chose these ESP8266 ESP-12F modules as they had a good rating. My mistake???? [NOTE: I used ESP8266 Firmware Downloader Flash Board Code Burner from Amazon to flash, LOVE this time saver, soooo easy, well worth $21]I quickly flashed and programmed the first 6 modules, #6 worked at first, then after about 1 hour of operation, the WiFi began dropping out then failed completely. I removed the module and ran bench tests. No WiFi at all, then it failed to hold a program, then it would not do anything...DEAD. Replaced the module with a new one, all OKContinued flashing new modules through #13. It flashed OK but the WiFi never worked. Re-flashed, checked, no WiFi signal at all. TRASHED! Last one flashed/installed OK.These appear to have serious quality problems. At a rate of 2 failed NEW modules in a lot of 15, 13% FAILURE rate is very BAD!I will be looking at a different manufacturer for the next batch of modules!!#######March-26, UPDATE: of the last 5 modules, 4 F-A-I-L-E-D, lowered rating to 1 star. 2 modules were in service for less than 4 hours then FAILED, tried to program 2 more, 1st OK, then within 10 minutes, WiFi FAILED, then, could NOT program/flash ANYTHING!

One unit from pack of 5 defective. Contacted seller, they communicated immediately and issued a partial refund for the defective board.