Coupling values are set so that the signal arriving at the coupled port lands within the useful range of the instrument measuring it, given the gain of the antenna underneath. At 26 dB typical this fixture takes approximately a four-hundredth of the radiated power, which is the appropriate sample from a high-gain aperture. The envelope follows the shape of the isoflux antenna, which itself stands 121 mm tall, giving the fixture a 76 x 76 x 132 mm (3 x 3 x 5.2 in) profile at 290 g. That is heavier than the flat X-band hats for the same reason. The RF shielded enclosure protects personnel during transmit testing and contains X-band energy within the test area. Mounting is on the antenna's own interface features with no spacecraft bracket required, and removal needs no tooling. The interface is SMA female, rated -70 to +100 °C operating and storage. CSA-X-004-RH is the matching antenna.