Based on the ESP-8266EX.
Arduino Compatible, you can use it on Arduino IDE.
11 Digital I/O pins 1 Analog Input pin
Insert pictures: description-01, 02,03
Tutorial Link:http://www.wemos.cc/d1/Getting_Started

Technical Details

Size (LWH): 4.6 inches, 3 inches, 0.6 inches
Product Details
Product Dimensions: 4.6 x 3 x 0.6 inches
Shipping Weight: 0.05 pounds (View shipping rates and policies)
ASIN : B016PNJ40W