Caseback is the back of the watch case. Often, a separate part forms a sealed back of the case. The case backs exist in several designs: solid, transparent, or open, usually incorporating sapphire crystal in cases with transparent case backs, which provides a scratch-resistant clear view of the movement inside. Probably the most dramatic characteristic of most watches is that transparent or exhibition case back, often pleasurable to observe because you can see the work of the movement inside in detail.