Years ago, my MA non-res was paper, and for years the MA res was a bit large (plastic, I think) that required an unusually large wallet or card case. Now all of mine (MA, NH, CT & FL) are plastic and driver-license size.
Plastic, protected picture like a drivers license. Renewal every 5 years. You supply a new picture every time and they accept a home-printed digital picture as long as it falls within the guidelines.
In MI they are a plastic card like your driver's license or a credit card.
They are also called a "CPL" (Concealed Pistol License) and with it you are only authorized to carry a concealed Pistol; not any other type of weapon.
Pistols only? No revolvers?
My MN permit to carry card is plastic.MN is paper. My daughter is an elementary teacher with a little machine that laminates.
Works good.