This Adapter Cheese Plate from Flowcine is meant to be used in combination with the FC-SLD Slide-In Option (sold separately) to enable you to mount the Gravity One on top of your Arri Alexa. The Gravity One can then be slid back and forth to adjust its position for achieving proper balance. This cheese plate also allows you to slide the Arri Top Handle onto your camera in place of the Gravity One.