The bright condensation 3C 153.I. Inside the HII region NGC 2175.

Physical parameters are derived for the bright knot inside NGC 2175 using optical dimensions 1' x 2' (Table 1). Photometry and spectrophotometry of the central star yield a spectral type O9-B0, a luminosity class `V-V and a reddening E (B-V) = 0.69 + 0.03. The central star is probably the source of excitation of the bright knot. Key words: H ii regions - evolution