Upper panels from left to right: WISE 12 μm, CGPS λ21 cm and Urumqi λ6 cm images centred at , . Small-diameter (<7′) WISE H II regions from Anderson et al. (2014) are marked by white squares and two extended WISE H II regions (diameter > 20′) are indicated by blue dashed circles. Three very extended radio sources in both λ21 cm and λ6 cm images are SNR G126.2+1.6, SNR G127.1+0.5 and H II region G127.9+1.7 (DU 65, Dubout-Crillon 1976, red rectangle), which is missing in the WISE H II region catalogue. Lower left panel: its Hα emission is shown overlaid by the λ6 cm total-intensity emission. Lower middle and lower right panels: TT-plot results for DU 65 by using the Urumqi λ6 cm against the Effelsberg λ21 cm data and the Effelsberg λ11 cm data.