Esp8266 with esp01 adapter

I have an esp8266 that came with an adapter that says esp01 adapter on it. I got the module working without the adapter. The adapter has Vcc, tx, Rex, and gnd pins. Does anyone know what the purpose of the adapter is?

Well it could be this or that or even an Aircraft Carrier is as good as a guess as any. Post an image of the adapter, please.

It's used for programing the module.

you can't program esp-01 with that adapter. it only adapts powering and logic levels and has boot config pull-up/down to run the esp-01, not for flashing. it is meant for use with esp-01 with AT firmware with 5 V Arduino

Thanks, that’s good to know. Any advantage to running it at 5 volts?

The on board voltage regulator takes a burden off the Arduino by supplying 3.3V to the ESP