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 and can be permanently mounted to any surface by being bolted or screwed in. 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 lets you know if your dock is connected to power.