The led card light is the same sizeas credit card and needs no wires.It is very convenient because you can place it inside the wallet. A such small card can be used for illumination, the design is so funny. The interior has a LED light bulb, when you need to illuminate, you can just fold "Light Bulb" up then the light will turn on. If you put " Light Bulb" down, the light will turn off. You can use it anytime and anywhere.Power supply: 3V Button Battery (included)Dimension: 8.6*5.3cmMaterial: ABS