I also collect Famicom but do not own a 3D System, because there are only about 7 games for it with most being Disk System games. Seems like a overly costly collectable as I also don’t own a Disk System.
This thing is alot like the VB. They float around on ebay from time to time, too. Anyway, this thing is used to look at a tv screen. It has the LCD flicker devices inside of it, and when it flashes on and off, it lets you see 3d! (Even though the graphics were 8-bit…) This thing sorta was known to cause headaches too. Sounds like the Virtual Boy again! If you have ever played rad racer on the NES, have you ever pressed select and the screen became red and blue? That was what changed, as the japanese version had the oscilating screens. I’m hunting online for one now. I hope to get one soon…