Covering 275 MHz continuously means the fixture matches the antenna it serves, removing the mid-campaign swap, re-seat and re-calibration that a narrower hat would force. Coupling is 1 to 4 dB with a 3 dB typical, measured against CSA-S-004-RH. That is a wider window than the narrowband L-band fixtures, which follows from covering roughly four times the bandwidth, and should be accounted for when setting pass and fail limits on a functional check. The RF shielded enclosure protects technicians during transmit testing and prevents S-band energy escaping the test area. The hat mounts on interface features built into the antenna, so no bracket is added to the spacecraft, and it comes off without tooling. At 97 x 97 x 64 mm (3.8 x 3.8 x 2.51 in) and 250 g it is the tallest of the standard S-band hats, which the wideband coupling structure requires. Rated -70 to +100 °C operating and storage. CSA-S-004-RH is the matching antenna.