A caseback refers to the back cover of a watch, which can be exhibition (transparent to display the movement), closed (opaque and not see-through), or solid (providing additional durability and protection).
The three main caseback types are: Exhibition (sapphire crystal window allowing movement viewing), Solid (opaque metal back, snap-fit or screwed), and Closed (older term for any opaque caseback). Exhibition casebacks showcase decorated movements and are popular on mechanical watches where the movement is a selling point. Solid casebacks may be engraved with model information, serial numbers, or decorative motifs. Screw-down solid casebacks provide better water resistance than snap-fit versions.
Exhibition casebacks use a sapphire crystal sealed with a gasket, providing water resistance comparable to solid casebacks when properly maintained. However, the seal degrades over time and requires replacement during service to maintain rated water resistance. For professional dive watches requiring maximum reliability, solid screw-down casebacks are generally preferred. Most watches with exhibition backs are rated to 30-100m—adequate for splashes and swimming but not serious diving.
Snap-fit casebacks use a notched edge and require a case knife or case back opener to pry them open—skill is needed to avoid scratching. Screw-down casebacks require a specialized case wrench with adjustable dies that fit into notches on the caseback circumference; never use improvised tools. Exhibition casebacks are typically either snap-fit or screwed, using the same opening methods. Attempting caseback removal without proper tools risks scratching the case, damaging seals, or rounding the opening notches.