Considering that the user added "portable" and "feature", perhaps the KK613D is a portable device. Maybe a projector, a light, or a camera stabilizer. Wait, sometimes Kenko has products like the Kenko Digital Teleplus, which are teleconverters. But the model number KK613D doesn't match any known products. Alternatively, maybe the user meant a different brand. For example, there's a brand called Kenko, but some products might have similar model numbers. Could it be a Kenko filter or lens hood but with a digital variant?