The walimex pro Double Clamp Block for video rigs serves the purpose of compensating for the difference in height between rig and lens. With the help of this clamping block another pair of rods can be attached to the rig for mounting accessories like e.g. a Matte Box. Since cameras with aperture battery grips are too high for the ideal attachment of accessories, the clamping block is the optimal solution for compensation. It can be used to match a vast number of camera/lens combinations. You find the separately available rods listed under accessories