This sale is for a Bronica ETRS / ETRSi Eye Correction Lens -3.5 D for the Rotary Prism Finder E, complete with 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 ETR prism, Just unscrew your existing dioptre and fit this in its place. This dioptre is very clean with minimal signs of use, just faint cleaning signs around the edge, no doubt easily removed, and otherwise perfect glass.
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 ETR series rotary prism. Waist level finders and other prisms need different dioptres.