Top panel: NuSTAR’s FPMA and FPMB average energy spectrum for OAO 1657-415. The continuum can be described by contributions of an absorbed cut-off power law and a blackbody. Gaussian distributions were used to model emission lines seen at ∼6.4 keV and ∼7 keV. Middle panel: residuals associated with the continuum model. Bottom panel: residuals associated with the continuous model plus cyclabs with depth equal to zero. A clear count flux deficit can be seen at around ∼35 keV.