Hey, Jim. Peter's post provides you with the semi-rigid postcard holder that your photo shows.
As for the key inside holder, I recognize the design and maker; I have bought them before. They are made of Mylar, which is the best protection in the industry, and produced by Bill Cole Enterprises. Contact them at
www.bcemylar.com. Go to their section on Mylar Sleeves; look for their chart on "small Gards". They seem to offer 2 types of 4 MIL. postcard Gards, a standard-size, and the Continental size, which is slightly larger. I believe this is what you're hunting for.
Kind regards, Brian Powell