This is a Vivitar Auto Wide-Angle 28mm F2.5 lens, with adaptable TX mounting system. It comes with a TX to Fujica ST adapter.
This particular lens is made by Tokina, as denoted from the “37…” serial number, which makes it a bit nicer than the cheaper F2.8 versions. It’s clean, very nicely made, operation is smooth and there’s no fungus or scratches.
The TX system was very similar to Tamron’s Adaptall offering, and made lenses adaptable to all major body mounts. This particular adapter is for Fujica’s ST mount which is an M42 screw mount, but with the addition of a means to allow open-aperture metering. This adapter/lens can be mounted to other M42 bodies like early Pentax, and Praktica but only stop-down metering will be possible.