Broadband spectrum of SXP 15.6. NuSTAR spectra are shown in black, and two NICER snapshots are shown in red and cyan. The upper panel presents the best-fit model composed of an absorbed cut-off power law and a soft thermal component. The ratio plots show the comparison of the tested models and the data: (b) Absorbed cut-off power law, (c) absorbed cut-off power law plus disk blackbody, and (d) cut-off power law with partial coverage. The model parameters are listed in Table 1.