Stutter card?

Stutter card? Hello there! Has anyone ever used or considered a ´´Hi, I have a stutter´´ card? I feel like it´s really useful because I block and people don't always know that you're stuttering. The fact that they know whats happening takes a lot of stress away and I can just take my time. Especially when you have a job where you speak to new people everyday, it can be exhausting having to explain it over and over again