Made by PENTACON, 28mm F2.8, 7 grp / 7 elm, filter size = ∅49mm, MFD < 0.25m, 230g
This is an earier version with metal barrel, the later version is made of plastic but optically same.
$60 & $20 @2006, the first metal one was a part of the package probably guessed $100 @2000

NOT same as PENTACON MC (electric) 28mm F2.8 (M42) lens, which is probably made in Japan,
yes there was Pentacon 29mm F2.8 lens, whose real name is Orestegon 29mm F2.8 made in DDR.

This lens is recomendable since it is not so expensive yet good enough sharpness w/o distortion.