Originally posted by elliott though it definitely did fall into the cheap price range.
Got mine in a box of other stuff, figure it cost $30. I also ended up with another one in pristine condition that came in another box of stuff, it wasn't even listed so it was quite a surprise when I dug it out of the old camera bag I bought.
@OP The idea of making extension tubes out of TC's has been around for a while. No one really makes extension tubes with contacts in them for Pentax so we have had to resort to 'extreme measures'. There are plenty of cheap tubes out there but good ones with contacts are scarce. As are modern TC's for that matter. I think the new Pentax 1.4x one has been on the road map but never delivered for maybe 5 years.