The Sears 135mm PKA mount is a decent budget lens but image quality can vary a lot from copy to copy. The unique feature is the varying level of softness that can be adjusted by the front close-focus ring. Basically this varies the amount of spherical aberration which contributes to the soft focus, diffusion filter effect. Like many other legacy MF 135mm lenses, it's a cheap lens so don't expect optical quality to be exceptional but a nice lens to play around.
Sears 135mm at nomal setting
Some softness at macro setting