The Nanao MS-2933 is a 15-31 khz autoswitch monitor (single focus), found in some Blast Citys, Net Citys and Initial D cabinets. It's very similar to the Nanao MS-2931, but even harder to find. A few components have different positions, also there's a small metal cage protecting some caps and an IC. The extended OSD can be reached by pressing the 'down' button for 3 seconds.
Tube: Toshiba A68KSM696X