Add four external USB 3.0 ports to your notebook or Ultrabook with a slim portable hub Compatible with HP ProBook 4540s Lenovo Carbon X1 Portable 4 Port USB 3.0 Hub Compact USB 3.0 Hub with Cable USB 3 Hub w Attached Cable Mobile USB Travel Hub Notebook & Laptop USB 3.0 Hub. Ideal for Ultrabook and MacBook users with limited USB 3.0 ports. Perfect laptop accessory adding USB 3.0 ports. Connect peripherals and multiple external hard drives in the home or office. Built-in cable.