P9 Dome Pushbutton Switches OTTO P9 Dome Pushbutton Switches are available in flush and raised dome button styles, and with a gloss or matte finish. The P9 Switches come with a threaded case for hex nut mounting or with a snap-in case. High contact pressure and a unique contact design provide low contact resistance for logic level switching capability, as well as, full-rated service. The switch series features short behind-panel depth and offers excellent mechanical and electrical performance while operating under severe conditions found in demanding applications.