Since this seems to be a complicated concept for some people to grasp, I've tried to make this design as clear and simple as possible. Is an invisible disability imaginary? No! It's still a disability, even if you don't think someone "looks disabled" (whatever that means).

This badge features the words, "My disability is:" over a crossed out checkbox that reads "imaginary" and a ticked checkbox that reads "invisible" on a white background.

It measures 38mm in diameter, and fastens with a sturdy safety style pin.