Presentation of I18308 cloud with three-color composite image, combining Spitzer 3.6 μm (blue), 4.5 μm (green), and 8.0 μm (red) emission. The dashed cyan loop outlines the ALMA mosaic field at 1.3 mm toward I18308. White contours depict 1.3 mm dust-emission intensities at [3, 9, 15, 27, 81, 243] × σ_{1.3 mm}, where σ_{1.3 mm} = 0.1 mJy beam^-1. Gray contours show cold dust emission from the single-dish MAMBO survey at 1.2 mm, starting from 5σ_MAMBO in steps of 5σ_MAMBO, with 1σ_MAMBO ~ 11 mJy beam^-1 (Beuther et al. 2002). The blue contour corresponds to a level of 25σ_MAMBO, encompassing the hub region. The blue and green crosses pinpoint the primary and secondary peaks of 1.3 cm free-free emission, respectively, typical of the (UC) H II regions (Lu et al. 2018). The synthesized beam sizes are 11″ × 11″ for the MAMBO observations and 0.71″ × 0.59″ for the ALMA ones, indicated in the lower left and right corners, respectively. A scale bar of 0.5 pc is shown in the top right corner.