The BT8390-SA allows B-Tech shelves and other accessory mounts to be fitted onto System X installations, making it the ideal solution for adding a VC camera to a twin screen setup. The arm hooks onto BT8390 mounting rails and can be positioned so that the mounted accessory is either above or below the screen(s). Featuring an adjustable extension arm that can be freely positioned anywhere along the length of the rail, the BT8390-SA is suitable for use with a large range of screen sizes.