For the photographers amongst us:

Keep away from Chinese lens adapters, try to get an old one instead! Or, in case of the PK bayonet, get the original adapter from Pentax (or Hoya who is the actual maker), it's the only one you don't need a release tool to remove it.

Chinese lens adapters for analogue cameras are easy to get either no name or branded like KF/K&F concept/kenfaith. In both cases, stay away from it. I've heard so many complaints about these adapters damaging the camera bayonet. Also, the Chinese often don't stick to the specifications, so the thickness of the adapter can cause focusing problems.
Btw, with the Tamron Adaptall2 adapters, KF even forgot about the mechanical parts needed for auto functions! (original Tamron adapters mechanically translate auto functions)

A good source to find old adapters are photo forums. Often, members switched to another camera system at some point and still have the old adapters.