RAM Mounts GDS Slide Dock is a scalable solution for charging multiple devices at once. It is designed to be integrated into a portable charging station and provides a universal charging dock for devices of any operating system. The GDS connector has an adjustable height connector to accommodate different devices. The adjustable height settings are numbered to quickly set up for any cart or charging station. The dock has a USB Type A male output that can plug into an existing USB port on a cart or into the GDS 6-port USB charger. There is an LED indicator light that turns red when your dock is connected to power. When your device is charging, the LED will blink green.