Cases exist in a variety of shapes and sizes and utilize a library of materials for construction such as stainless steel, gold, ceramic, titanium, plastic, and more. The dominance of stainless steel in case construction remains, however, hypo-allergenic metals and materials, like titanium, continue to gain in popularity. Metal cases often have particular finishes - such as a smooth reflective polish or circular matte brush - that enhance the presentation of the timepiece and give it unique depth.
Some designs allow for the case and lugs to be curved in order for the watch to have a more comfortable fit around the wrist. The back of a case will typically be removable and most likely be screw down or pop-off. It is important to note, however, it should only be opened by a trained professional. An exhibition feature (found within a case's back) refers to an added window that allows you to view the movement and is often found on automatic and mechanical timepieces.