XPS technology in the DeWalt miter saw is an LED light system that projects a shadow on both sides of the blade. It forms a shadow of the blade on the workpiece you are cutting. When you lower down the saw head, the shadow goes sharpens and darkens and shows exactly the place where the blade will meet the workpiece.
The XPS LED system is hard-wired in the power of the miter saw. There is no separate power supply or batteries to help you power up the saw. There is a switch under the handle that controls the on/off of this mechanism.