With incredible accuracy, the Patented Infrared Screen Set eliminates the need for sunlight when using the CED Millennium Chronograph system, and gives you the freedom to record velocities under any lighting condition, or if you choose, no light at all! Connects to the standard sensors that come with the basic system, and uses its own AC power source or optional NiMH battery pack. The Infrared Screen Set includes Infrared Screens, side-arms, AC Adapter, and instructions.