ENERGY SAVING: Each layer has an independent switch which helps you to save electricity when the other outlets are not in use. Due to different voltages in different areas, this surge protector power strip tower is designed to support 110V-240V. If it is used under 125V, the max power will be 125V x 13A = 1625W; if under 240V, the max power can reach 3000W. Please do not exceed the totall wattage. Formula P=UI.(P=Power, U=Voltage, I=Current) | SPACE SAVING: With the vertical tower design, JACKYLED charging station helps you to save space and you don’t need to worry about big plug blocking the other outlets. | SMART USB PORTS: The 4 USB ports (max total 5V/ 2.1A, each port up to 2.1A), can charge two cellphones together, or one iPad, MP3, digital camera, tablet at fast speed. (Note: USB charging may not work if the total current exceeds 2.1A). | SAFE & RELIABLE: RoHS, CE & FCC Certificates. This power strip with USB has surge protection (900J), overload protection, short-circuit protection, over current protection, over voltage protection and overheating protection. It will automatically cut power to protect connected devices when voltage surge is overwhelming. | RETRACTABLE CORD: With the 6.5ft pure copper retractable cord, you can roll up the cord by rotating the tower, which can make your desk tidy and you can set the cord length to your need. A durable handle on the top for convenient carry. Warm tip: please do not use a non-standard adapter or an electrical plug to avoid causing a short-circuit.