X Per average spectrum with ISGRI (black diamonds), JEM-X (red triangles), NuSTAR/FPMA (blue stars), and FMPB (green squares). The best-fit models are overplotted with comptb+comptb (long green dashes), comptb*gabs (short magenta dashes), comptb+gauss (cyan dots), and CompTT+CompTT (red dots and dashes). The folded spectrum with the comptb*gabs model is shown as an inset. Plots of the residuals for the comptb+comptb, comptb*gabs, comptb+gauss, and CompTT+CompTT fits, respectively, are plotted in panels below the spectrum. Dashed lines are plotted at ±3σ.