With a few minor tweaks and upgrades the IO-12 is essentially an O-10 first introduced by Heath in 1955. Back then most low cost scopes had bandwidths well under 1MHz. The O-10 was specifically designed with a 5MHz B/W so it could display the NTSC 3.58MHz color burst signal for the newly introduced color TV standard. But there were trade offs in the design such as a non-linear sweep as shown in this video.