Paul Murray wrote:

My father-in-law has come to stay, and dropped off an interesting present he
thought he had lost years ago, but has just found again.
It is an eyepiece adapter than connects directly to a Pentax-fit lens, and
allows you to use it as a telescope. He say he thinks it has an effective
10x magnification, so that a 200mm lens becomes a 2000mm telescope.
It is certainly useful for birdspotting around the garden.
Written around the adapter is
"BOB PATP 54038748 APK TELEPHOTO LENS ADAPTER JAPAN"
Does anyone know anything more about this piece of equipment?

Pentax made this monocular converter:
http://www.bdimitrov.de/kmp/lenses/adapters/monocular.jpg Does it look
familiar?

Mr. Dimitrov says this about it: "The monocular converter K converts K
mount lenses to monoculars. It provides magnification equal to that of a
lens with five-times the focal length. For example, a 50mm lens appears
to be 150mm and a 300mm lens appears to be 1500 mm." (Maybe the 105mm
part is a typo?)

More than you ever wanted to know about Pentax K-mount stuff is right
he http://www.bdimitrov.de/kmp/