Left two buttons are used to adjust volume.Right two buttons are used to switch FM stations.The switch on the side is the power switch. UP is ON and down is OFF.It is a simple FM receiver and can be used all over the world with power by 18650 rechargeable battery.It is very suitable for users to learn electronic circuits, practice and proficient soldering skills, and enhance electronic professional knowledge and interest.Universal frequency 87MHz-108MHzPerfect simple circuitDIY hand solderingStable fixing bracketSupport battery charging functionProduct Name: RDA5807 FM Radio Receiver DIY KitWork Voltage:DC 3.7VPower Type:18650 Battery(Not Included!)Work Temperature:-25℃~85℃Work Humidity:5%~95%RHMaterial: pcbcolour: greenPackage Contents:1 x FM Radio DIY KitOnly the above package content, other products are not included.Note: Light shooting 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.