I found that the a lot of my student have mastered the whole "you put one picture in front of me, and I touch it" phase, but weren't actually paying attention to the pictures - just hitting whatever what in front of them. Voila! A two choice mini book, which is still probably small enough to fit on your key ring. Now if they don't look at what they're touching, they won't get what they want - a good incentive to look!
I arranged them with a whole bunch of tab choices for you, so you can easily find a concept (just cut off all the tabs you're not using). Put a hole and a binder ring through the upper left corner, hook onto keychain or belt loop, and poof! portable two choice communicator.
Plus, with the exception of one picture (I could not find a good photo for books!), it's all photographs, which should help those of your children who have trouble with object-symbol correspondence.
You can also print front and back (select flip on short side) to save some paper and reduce the number of pages.
Finally, I know the thumbnail looks weird, but TPT always messes up my thumbnails. Don't worry, text is black and the formatting is fine.