That's what the package says but we have no clue how to use it. At first glance it looks like an eyepiece, but it isn't. Front element is flat difuse glass, then seperated about 15mm and secured by a retaining ring is a dark glass filter. Filter is 14.9mm diameter by 2.3mm thick. Some visual light gets thru. Knurled metal barrel is 33.6mm diameter by 35.2mm long. Unused in original packing.
