Galaxy S4 Charger - Battery Charging Station, AnoKe USB 3.0 Desktop Charging Docking Station Cradle - Support Charging Spare Battery for Samsung Galaxy S4 I9500 Mobile Cell Phone Charger Dock This charging dock cradle is specifically designed for Samsung Galaxy S4 Function: Data synchronization + Phone charger + Phone holder + Charging Spare Battery (not include battery) Small portable design, easy for cell phone charging with travel. Stable phone holder allows to watch movies without hand holding all the time,The dock works with TPU / PC slim case or without case Notes:The dock is equivalent of a connector. If adapter output voltage is not enough, maybe cannot charge phone and battery at the same time. Just work either. If the special adapter over 18w (quick charger 2.0, quick charger 3.0 )have enough output voltage, both battery and phone are charging. After-salaes Service: If you have any questions about product, please contact us via Amazon message system.The best way to slove problem is communication, please do not to leave a neutral or negative review before contacting us. we will reply within 24 hours.The pursuit of the highest quality product and the best service is our persuit. Wish you have a pleasant buying experience.