The full legend should read "SMC PENTAX 1:2 85mm 1:2.8-4 100mm".
They may have issued some of them without the 85mm mention as this lens came out a bit afterwards.
I use it on the aforementioned lenses on film, and it makes a dandy hood for the SMC-P FA 70-210mm on film as well. It also works as an extended lens hood on the 43ltd 50mm and 55mm focal lengths on APS digital.
Out of it, I carved a nice tulip hood for the M20/4.
Andre
