Description This is a reliable USB battery box for string lamp. It is designed specifically for string light power supply. Selected good material, not easy to deform or break. Simple in structure, very easy to operate. Fine workmanship ensures the durability and practicality. Features - Color: Transparent - Material: Plastic, Button battery - Size: 8.50X6.00X2.20cm/3.34X2.36X0.86in - Powered by: 3 x AA Battery(no included) - Input voltage: 4.5V - This designed specifically for string light power supply. - Fine workmanship ensures the durability and practicality. - Simple in structure, very easy to operate. - Selected good material, not easy to deform or break. - Carefully designed, excellent for use. Good quality and . This designed specifically for string light power supply. Fine workmanship ensures the durability and practicality. Simple in structure, very easy to operate. Selected good material, not easy to deform or break. Carefully designed, excellent for use. Good quality and .