The DRR receives the signal from either the remote controller, or the transmitter. After installing the DRR to the top of light housing, turn on your Mobilight DC-600/1000 and the digital display will show you the light number and output reading that it is receiving. The 360° adjustable supporting holder ensures that the DRR always faces the signal resource (the DRR is included when you purchase a JTL Mobilight DC-600/1000, but additional receivers can be purchased separately as well).