Here is a link to a video:
https://www.youtube.com/watch?v=AWao0RY0ZWgIt seems to work by pushing on the (raised) arms, so I think neckwear would not be a problem, though some styles of arms might not fit.
I find the early klickies actually
easier to pull apart (I can do most of those by simply tugging on the head), but ones with the white skeletons nigh on impossible without a rubber band.
The design shown in the video might be easier to operate one-handed I think, whereas the one with a handle to wind might be trickier, I'd like to hear from someone who has tried both. But having to wind the thing back again every time (either model) would be a bit annoying!
There is an email address at the end of the video. If I find out more I will add here.