The iPhone Duo has two displays: a 7.6-inch folding inner display at 1878 by 2670 pixels and 430 ppi, and a 5.4-inch outer display at 1398 by 2034 pixels and 460 ppi. Both are Super Retina XDR OLED panels with ProMotion up to 120Hz, Always-On and 3000 nits peak outdoor brightness, according to Apple’s tech…