The Nikon AF-S TELECONVERTER TC-20E III is an aspherical teleconverter with a 2x magnification factor. It has been stored in a dehumidified storage box. There may be some minor dust particles inside the lens, but they are minimal. There is no mold. I was using it until recently, so there are no operational issues. I used this teleconverter with a 70-200mm lens when I wanted more telephoto reach, but I've purchased a telephoto lens and no longer need the teleconverter, so I'm selling it. It is only compatible with Nikon lenses that support teleconverters. I have taken good care of it, so it doesn't show much wear and tear, but please refrain from purchasing if you are concerned about minor details, as it is a used item. I don't recall dropping it, but there is a small dent. Returns are not accepted after purchase. If you have any other questions, please ask before purchasing.