Note: There is no mobile power comes with the backpack inside. There are two models,With USB and Without USB. Large size : 48cm*31cm*17cm,fit 15.6 inch laptop Middle size : 43cm*26cm*12cm,fit 13 inch laptop 1 Inch = 2.54CM; 1 CM = 0.39 Inch. Please allow 1-3cm (0.4~1.18") differences due to manual measurement, thanks. With USB: Without USB: Item color displayed in photos may be showing slightly different on your computer monitor since monitors are not calibrated same.