This lens is made by PENTACON, optical design is the same as later 50mmF/1.8.
The lens looks like CZJ made one, but the internals are in cheap Pentacon style.
4 grp / 6 elm, MFD = 0.33m, filter size = ∅49mm, 226g, CZJ style lens barrel
$20 @2002, $20 @2002

This lens is "relatively rare to find", has (unusual) nice deep blue colour coating.
Me thinks there were lots of CZJ 50/1.8 parts, so PENTACON used them to make
their own newer Prakticar 50mmF/1.8 cheaply with a different optical one.