SDSS DR8 colour images of the polar ring sample (see Table 1). The scale bar in each image is 10 arcsec long, and the two dashed circles indicate the full width at half power (FWHP) beam width for the CO(1–0) and CO(2–1) observations. To identify the polar systems, we have indicated their directions with arrows, corresponding to the PA displayed in Table 1. SPRC-33 contains a giant HI polar disk with very weak stellar counterpart detected in UV images only (Bettoni etal. 2010; Moiseev etal. 2011).