This Chip on Board COB Led Light is a very small and innovative product, it comes in many different Shapes and Sizes. Its mostly used where the thickness of the product is a very important consideration. These led come with an aluminum metal back which acts as a heat-dissipating area for the Led, as these led got hot while running. Input Voltage:- 3.7V- 4V Max Input Voltage:- 4v (More than 4v Voltage will completely damage the product ) Aluminum Back as a heat sink.