Hasselblad diopter used with the PM45 or PME45 Viewfinders. This optional correction lens is designed for shifting the normal eyepiece diopter range of -2 to +1 diopters. When attached, the range becomes:
+0.5 to +3.5 with #42467 (+0.5 to +3.5 diopter for the PM45 and E45-prisms)
-4.5 to -1.5 with #42469 (HADM4.5M1.5P)