This is a rare, low-mag plan APO scanning objective (1.25×, na 0.04) with a very wide, flat field and decent wd (~5.1 mm). It’s RMS-thread and infinity (olympus UIS/UIS2).
The adapter included will allow the objective to fit in a standard Olympus 26mm M26 size nosepiece. The objective itself has a 20.32mm thread (0.800" 36tpi standard).
