The iBOLT Perfect Fit Charging Dock for Galaxy S3 and S4 is a real active car-dock. It triggers the DockMode when microUSB side arm is inserted. Download the iBOLT Dock'n Drive App (free on Google Play) for an optimal driving experience that includes your favorite Apps and Direct Dials as large icons, a GPS enabled speedometer & compass and more. Enjoy listening to the music or GPS directions through your car-stereo speakers thanks to the integrated aux-out cable (car must have 3.5 mm aux-in). Note that phone calls are not transmitted to the speakers due to Samsung firmware limitations. Most cases fit when insert is removed, up to the size of Otterbox Commuter okay but Defender style case does NOT work. Expect a completely vibration free driving experience with the ROK II Solid suction mount. Attach to windshield, or stick directly onto hard surface on dashboard. A ball-joint connector system allows the driver to adjust to almost any viewing angle. The female ball connector on the Dock is a 17 mm "industry standard" size, allowing any dash, vent or bike mount designed for Garmin to work with the cradle as an alternative to the suction mount. Backed by iBOLT's excellent customer service. 1-year manufacturers warranty. Stay safe!