SOLO S4 uses only a fraction of the power used by conventional corded detectors. Using 2 standard (AA) batteries (included), the SOLO S4 radar detector provides months of normal driving protection. A new low-battery warning circuit keeps constant watch on the condition of the batteries, and provides you with both audible and visual alerts before they need to be replaced. A new AutoPower feature (programmable) automatically turns the SOLO S4 off to conserve battery life.