This sale is for a Bronica SQ / SQ-Ai Eye Correction Lens +0.5 D for the Prism Finder S and AE Prism Finder S, unfortunately without the original storage case. Please see my other listings; I have other dioptres available.
This dioptre simply replaces the standard -1.5 dioptre supplied with every Bronica SQ prism, Just unscrew your existing dioptre and fit this in its place. This dioptre is very clean with only very minor signs of use, and nothing that will in any way affect you using your prism.
A large (but definitely nowhere near complete) selection of Mamiya, Bronica and Fuji GX680 dioptres available and I do not have time to list them all; if you cannot see the one you want then just ask.
Note that this dioptre is not suitable for any Bronica finders except the SQ series prisms. Waist level finders and the ETR and GS-1 systems need different dioptres.