The GoCoupler 90° allows you to attach an additional GoRail at the end of the SystemGo center column. This allows the GoRail to become height adjustable and you can mount a ballhead and/or other SystemGo accessories to the top of the GoRail. This is ideal for multi camera shoots or for turning your SystemGo tripod into a mobile workstation. The GSC290 is compatible with any 2 series SystemGo tripod.