Promotional Kustol 4,000 mAh, external auxiliary battery. Inside LED light and body especially designed for laser printing, illuminating the logo. Charging indicator, with USB output and micro USB input -cable included-. Wide printing area . The capacities shown in all our external auxiliary batteries are real, all of them incorporating non-recycled, grade A batteries, with a service life of at least 500 charging cycles, and complying with CE regulations. In addition, they are manufactured according RoHS standards, and in compliance with the following safety requirements: Power bank overcharge protection system. Complete discharge protection system, which increases the durability of the power bank. Blocking system to prevent short circuits. Constant charging transfer system, in accordance with the capacity of the target device.