This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
I can't be sure since I can't see clearly but the second to last item looked to be a 2 bit Gray Code switch which allows one to measure relative rotation position and direction of rotation of the spindle. I have some of these on order from China and am currently writing the code for them. I'm going to use them to select options on an instrument I am constructing. They are a lot cheaper and more flexible than multi-pole multi-way switches that I would otherwise have to use.