Completely self-contained string of tiny holiday lights has small white power unit with batteries installed. Add these clear lights to hundreds of items for a warm attractive glow. Complete with batteries and ready to go - just pull out protective plastic film from power unit and turn slide switch "on". Control unit is only 2" x 0.9" x 0.25". Warm white string of 20 LEDs is a little over 6ft long. Brand new!