The YU YUREKA BLACK specs include 5 - inch IPS 2.5 D curved glass display with 1920 x 1080 pixels resolution, 441ppi pixel density and houses Corning Gorilla Glass 3 for added scratch resistance. (techandroids.com)
The OPPO F7 Diamond Black specs include 6.23 - inch IPS display with 2280 x 1080 pixels resolution, 19:9 aspect ratio and multi-touch support. (techandroids.com)
If there is any debris (for example small black specs), place this on some damp cotton wool — if these are flea dirts, they will slowly dissolve leaving red - brown blood marks. (icatcare.org)