Tiny optic that some will find useful. Set up the GR3x to point and shoot and use this optic instead of the screen. It is unobtrusive and very effective. It is, however, the most overpriced accessory in this galaxy. I would buy it again for the function that it enhances. It merits 5 stars except for the price.
I don't actually use this on a Ricoh GRIII or any other GR model. I use it on my Leica M's , and the Leica III and its clones. The optical quality is on par with Voigtlander viewfinders and so is the price. You get what you pay for, I guess. The view is impressive, bright, and extremely useful.