Near-IR color–color diagram indicating the regions for different categories of objects defined by GL97 (separated by thin full lines), Siódmiak et al. (2008 – thin dashed lines), and Bessell & Brett (1988 – thick lines). Triangles are used to show our stars and gray circles represent very likely post-AGBs from the Toruń Catalog. Double-peak SEDs are indicated by filled symbols (post-AGBs class IV). Gray crosses represent the HAeBe stars from HBC.