4,000 mAh, high charging capacity external auxiliary battery, convertible in mobile phone holder. With charge indicators and micro USB cable. Large printing area and presented in an attractive design box. 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.