Actor Frank Puglia is listed in the on-screen cast list but does not appear in the episode. He was, however, in "The Concrete Overcoat Affair: Part I."
The sound barrier reflecting disk is the death ray prop from the movie "Atlantis, The Lost Continent."
Will Kuluva, who portrays THRUSH Central bigwig Mr. Thaler, was originally cast as the head of U.N.C.L.E. in the original pilot for the series. He also plays the same role in To Trap a Spy (1964), which is the original series pilot edited and expanded for theatrical release.