One specification that curved monitors have and flat ones do not is a number/letter combo that looks like 1000R, 1800R, 1900R, and so on.
This spec represents the curvature of the monitor or the magnitude of bending. The R here stands for radius and is measured in millimeters. When we say the radius is measured in millimeters, we mean the span that forms a portion of a radius, determining curvature. Keep in mind monitor curvature and size are not the same and the number does not refer to the width of the monitor, but only to the radius.
The lower the number, the more curved the monitor. For example, 1000R forms a portion of a 1000mm radius which is a very popular curvature, and is more curved than 4000R. So the bigger the number, the less pronounced the curve.
That’s in general, because it is technically possible to make a 49” 1000R monitor, but that would be an extremely aggressive curve, with the edges nearly touching each other due to the combination of a very wide monitor and very pronounced curve.
Two more features to keep in mind are screen ratio and resolution. Curved monitors are almost always ultrawide 21:9 or 32:9 by now. That’s different from the 16:9 of nearly every flat monitor. So please remember curved monitors use ultrawide native resolutions, like 3440 x 1440 and 3840 x 1600. These are modified QHD and 4K resolutions, and while they look great, not every game supports them, and many desktop apps may not look right. Just remember that when deciding on a curved display.