Solar hard X-ray spectral measurements collected by the RHESSI mission, stored in standard FITS (Flexible Image Transport System) format. Each FITS file includes count spectrum files for every orbit of the RHESSI mission (midnight-to-midnight) with 4-second time bins and 77 energy bins covering 3–250 keV, combining all functional detectors. For each flare interval, corresponding Spectral Response Matrix (SRM) files with the same energy binning are also provided. These FITS files are written by the routine hsi_ar_sp_main.pro and can be displayed and analyzed in OSPEX (OSPEX documentation). In the OSPEX GUI, these files can be automatically located and downloaded based on the selected time. The purpose of this directory is to provide uniform, calibrated, analysis-ready data products that ensure accurate and reproducible scientific results.