An unusual type of supergiant semiregular variable (type SRD) of spectral type F found at high galactic latitudes. Amplitudes range from 0.1 to 0.6 mag. and the periods are from 40 to 100 days. Only a handful of examples are known. UU Herculis itself appears to have two periods, of about 46 and 71 days, and a brightness range of mag. 8.8–9.3. Its spectral type is F5Ib.