E means that the product is rated in its category in terms of energy efficiency. The Energy Labeling system is based on EU Regulation 2017/1369/EU. E AOC 24G2SAE/BK, 23.8", 1920 x 1080 pixels, Full HD, 1 ms, Black, Red AOC 24G2SAE/BK. Display diagonal: 23.8", Display resolution: 1920 x 1080 pixels, HD type: Full HD, Display surface: Matt, Response time: 1 ms, Native aspect ratio: 16:9. Built-in speaker(s). VESA mounting. Product color: Black, Red