If you have a PTSD Support / Service Dog and are constantly barraged with questions, or just want to help raise awareness, feel free to modify them and make your own. I got postcards printed at VistaPrint for a very reasonable price.
They have been very well received by everyone I've given them to... The staff ladies at a tourist attraction we stopped at told me that Ben was the best part of their day, and they were really interested to learn about his job.
Oh, and when we got on the Aquabus on Vancouver, the guy at the dock read Ben's jacket tag and muttered (mostly under his breath) "PTSD dog ... Cool."
Made my day, that did.