This hub works without the power adapter.you only need the power adapter to use the smart charger port on the side.some info I found online:[ 5V Power Adapter & Advanced Chipsets ] BYEASY USB 3.0 data Port HUB is working both bus-powered and self-powered. The Powered USB 3.0 Hub has equipped with a 5V power adapter that ensures safe & steady data transfer for all connected devices. Advanced chipset with good thermal design, will not heat even if used for long time.USB hub 3.0 Splitter made of high-quality aluminum alloy and ABS design, Sturdy and durable, compact and not easy to move that fits naturally for home and workplaces.[ Smart Charging Port ] This USB expansion hub come with a fast charging port allows to charge cellphones, tablets, camera and speakers and more, and automatically detects and delivers the optimal charging current. The USB 3.0 Port Expander Provide up to smart charging for your smartphone, tablet, and other USB-charged devices, including Android,and iOS devices etc.