For the WiFi module A adapter module of ESP-01. The 3.3V voltage regulator circuit and onboard level conversion circuit easy for 5V microcontrollers to be used with ESP-01's Wi Fi module. In addition,the product can be used with for 's UNOR3 or compatible board. Design: Compact and robust design,perfect for and long-lasting use in all types of environmental conditions. Working voltage: 4.5-5.5V (onboard 3.3V LDO regulator) Working current: 0-240mA Interface logic voltage: 3.3V/5V compatible (onboard level conversion circuit) Due to different batches,there may be differences in product appearance and printed text,which will not affect use Colour:Blue Material:PCB Package Contents: 10 set x WiFi Wireless Adapter Module (10 adapter plates + 10 EPS01) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.