C 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. C Lenovo C24d-20, 61 cm (24"), 1920 x 1200 pixels, WUXGA, LED, 7 ms, Grey, White Lenovo C24d-20. Display diagonal: 61 cm (24"), Display resolution: 1920 x 1200 pixels, HD type: WUXGA, Display technology: LED, Response time: 7 ms, Native aspect ratio: 16:10, Viewing angle, horizontal: 178°, Viewing angle, vertical: 178°. Built-in speaker(s). Built-in USB hub. VESA mounting, Height adjustment. Product colour: Grey, White