This is an M42 threadmount lens in good condition. Its a constant aperture f4.5 and the glass is in perfect condition. Focus and zoom rings are smooth and aperture rings (and diaphragm) functon with no sticking. It has an aperture preset ring. The only two flaws are that the tripod mount has a minor crack and the mount ring has someones initials scratched into it. Neither of these affects function.
The M42 mount can be easily adapted to most DSLRs. I have two adaptors myself that I can show you. They were about 12 dollars each.