The complete set of nested Chandra X-ray mirrors (4 shells with 2 segments - parabola and hyperbola - each) and their support structures make up the High Resolution Mirror Assembly or HRMA.

Reference:

Van Speybroeck L.P., Jerius D., Edgar R.J., Gaetz T.J. & Zhao P., 1997, SPIE, 3113, 89

See the POG for technical details. The CXC HRMA Calibration webpages have the latest calibration status.