The WRX-1003 is an ARCA compatible Tripod Mounting Block for the Phase One XT Camera. This adapter allows you to mount the Compendium from the bottom of the XT Camera. Before the introduction of this adapter you would have to remove the metal panel on the side of the camera to mount a compendium tot the XT. The WRX-1003 comes with 16.5cm support rods. Its also is available in the WRX-1002, which also includes a compendium. Below is a short instructional video that explains the easy installation.