An opto-electronic display uses light-emitting elements — such as LCD, LED, or similar technology — to present the time digitally. 'Other display types' in 910219 captures battery-powered wrist watches that use neither a purely mechanical analog display nor an opto-electronic one, such as certain electroluminescent or hybrid displays. Confirming the display technology in the product's technical specifications is essential before selecting the subheading.

Yes, provided the article is classifiable as a watch under Chapter 91 in the first place. Stainless steel is a base metal, so a watch with a stainless-steel case that is not clad with precious metal belongs under 9102. The further subheading depends on whether it is battery-powered or mechanically wound and, for battery types, on the display technology.