The flight array consists of four modules mounted together on a frame, but thermally isolated on fiberglass box members. A thermal strap goes to a heat sink at the side of the instrument, which is connected by a thermal strap to a button on the side of the helium vessel in the SIRTF cryostat. Because the stressing hardware takes a lot of room, we use reflecting cones to bring the light down onto the detectors. In this way, we have response over the full pixel area, not just in the center.