Initially sold for ¥330,000
The GM1 is one of the CRT monitors available within the first YIS ecosystem. This colour "video display" can also double as TV screen for the VHD player and is the higher tier of monitors available. A (monochrome?) cheaper GM2 dedicated only to computer graphics was also on sale. Yamaha never made monitors for the MSX line of computers, so these ones together with some terminals like the YGT100 may be the only CRTs Yamaha ever sold to the public.
The display connects to the central processing unit via a 15-connector. No other details are available at the moment about these objects. There's probably a flap on the right side but controls were never shown on press materials.
Optional GM1-ST wooden case was sold separately.
Note: the illustration is based on very blurry picture and thus may not represent perfectly the actual object. Unlike the PU1-20, its KB1 keyboard and the PC1, no other YIS component has surfaced on the Internet so far. It's highly possible one of the front sliders was dedicated to volume instead of contrast.