Spectrum of AME-G353.05+16.90 in the ρ Ophiuchi West molecular cloud. The best-fitting model consisting of free-free (orange dashed line), spinning dust, CMB (black double/triple-dotted line), and thermal dust (light blue dashed line), is shown. The spinning dust model consists of two components: high density molecular gas (magenta dot-dashed line); and low density atomic gas (green dotted line). The 100/217 GHz data are contaminated by CO line emission and are not included in the fit.