Around 1924 the patents and rights were transferred to General Optical Company of Mount Vernon, NY, which had been making a much larger, heavier and more solidly encased instrument, called the Genothalmic Refractor, since around 1920, using Woolf's 1917 patent number, and with a user's manual dated 1921. This instrument had a range of +17.75 to - 22.50, and up to -3.75 cylinder, Maddox rods, Risley prisms, and a Steven's phorometer. It weighed 7 pounds 5 ounces, and unlike all earlier devices of this kind, it hung from a horizontal mounting bar instead of being supported from the bottom. Like the Woolf, it had no Jackson cross-cylinders (JCC) at first, so a separate hand-held one was required. Late models of the Genothalmic were fitted with JCCs.