Crab nebula SED derived using csspec. Red data represent the unbinned csspec analysis, the red curve is the curved power-law model fitted by ctlike, and the light red band is the 68% confidence level uncertainty band of the model fit that was determined using ctbutterfly. The blue curve is the power law with exponential cut-off obtained by Aharonian et al. (2006a) for dataset III, and the green curve is the curved power-law obtained by Nigro et al. (2019).