The Asahi Auto-Takumar 105mm f2.8 is a moderate tele lens for 35mm SLRs with M42 mount.
This telephoto lens was produced with the same four element design as the Takumar 105 mm f/ 2.8 Preset (http://allphotolenses.com/lenses/item/c_2483.html). The first one was the Preset version, the second one the Auto-Takumar version. The Auto-Takumar version has a semi-automatic mechanism for opening the aperture for "bright field focusing". This mechanism was the precursor to the true automatic mechanism employed in later lenses.
While optically the same, these two lenses are very different in their exterior physical manifestations, having different weights, filter diameters and arrangements of focus and aperture rings.