what kind of mount is this & how do I attach it?

[hifisapi]

I picked up this lens real cheap at a thrift shop. Its a vivitar with some kind of detachable automatic mount.
Problem is I don't know how to properly attach the mount. Any clues?

[casualcollector]

Ring at the rear of the lens is a lock ring. Rotate it completely open, towards the "O". Match the arrows of lens and adapter and mate together. The short pin is a registration pin and it will fall into place. Rotate the lock ring closed, towards the "C". The little silver button on the plastic housing is a spring loaded latch. You'll hear it ratchet closed. To remove the adapter, press the silver button while turing the ring towards "O". Learn more about this system here.

https://sites.google.com/site/casualcollectorproject/Home/lenses/t4-for-two

[luisalegria]

You have the word from the T4 authority !
BTW, I find that lens fair. I have the Soligor version. The Vivitar should be identical except for the cosmetics.
Please let us know how it works for you.