Photographic reduction up to a 2 "T2 (M42x0.75) thread with an optical length of 40 mm is the optimal way to attach a camera or T2 camera to a telescope, with a large active aperture, eliminating vignetting often present in 1.25 "adapters. The adapter is also an effective extension (40 mm), useful when the range of the extractor is not enough for sharpening. The adapter is equipped with a 2 "filter thread from the bottom. Material: anodized aluminum.