sreen size >7.8 inches for certain tablets? "According to the FCC, the new V-chip rules will apply to digital television receivers displaying images in a 16:9 ratio, with displays that are 7.8 inches or greater in height. V-chip technology must also be included in all digital television receivers with integrated 4:3 displays measuring at least 13 inches diagonally."
(https://www.pcmag.com/article2/0,2817,1930598,00.asp)