Regions used to extract filament and background spectra for the case of J1214+2712. The image was generated from 0.2–2.0 keV event lists from eRASS1 data. The green solid box represents the “full length” region, the red solid box represents the “segment” region, and the cyan solid boxes represent the region used for “local background” extraction. The magenta solid and dashed circles represent R₅₀₀ and R_vir of the clusters, and the white dashed box is HUBS FoV of 1° ×1°.