SEDs of four YPNe from 0.1 μm to 100 cm. Available radio data are shown as filled rhombuses, Herschel photometry as crosses, WISE detections as open diamonds, IRAS photometric measurements as filled circles, MSX results as open rhombuses, SMSS u-, v-, g-, r-, i-, and z-band measurements plus other optical photometric data as open squares, AKARI photometry as asterisks, 2MASS results as open triangles, and DENIS data as filled triangles. The IRS spectra of three nebulae (H 1-8, H 1-43, and K 5-4) are also plotted. The UIE features at 6.2, 7.7, and 11.2 μm and several silicate bands at 23,28, and 33 μm can be seen in the fits. Note that some 12, 60, and 100 μm IRAS measurement results are upper limits. The green, blue, and red curves represent the total fluxes of all components, the best-fit values estimated using the DUSTY radiation transfer model (Ivezic, Nenkova, & Elitzur 1999), and the nebular contributions, respectively.