Some cordless impact drivers have a battery-level indicator which lets you know how much battery power the tool has left. The location of the battery-level indicator will vary depending on the make and model. Most are can be found on the end of the impact driver as shown on the left.
What are the advantages?
Having a battery-level indicator on your cordless impact driver is like having a fuel gauge on your car. Knowing when the battery is about to run out means you can prepare for it, rather than being caught off-guard when the tool stops in the middle of a task.
A battery-level indicator gives you a good idea of how much battery power is being used when working with certain materials or screws. For example, working with tougher materials and larger screws will typically use more battery power to produce the required torque.