If you have a Wemos D1 mini card and you want to test the series of sensors contained in the package "37 in 1 Sensor Module Board Set" which is sold by many sites you can use this shield. On the shield are available many connectors that are already properly connected with the digital or analog ports of the Wemos D1 mini card. On the board there is also already a power supply stage that allows powering everything for example with a 9V battery. In fact, in addition to the sensors in the "37 in 1 Sensor Module Board Set" kit, the board allows testing other sensors, servo, etc. for a total of over 50 types, the presence of an I2C bus connector further expands the type of devices that the shield allows. If the relative OLED Shield is mounted on the Wemos D1 mini, the measured values or the logical states can be viewed on the 0.66 "64 x 48 pixel display. For more information see this page