I searched all over to find just the right density of foam for our customers and students to use. Once I found it I bought it in a large quantity, and have it cut in Large and Travel size boards for your convenience.
TIP: To prolong the life of your foam board, consider this: you should not be stabbing your needle into the foam as you are needle felting! Quite a revelation for some, but think about it. By driving the fibers into the foam board every time your stab, you are doing two things--destroying your foam and creating a fuzzy surface on the underside of your project that you then have to peel off the board, (and often little bits of the foam board with it). Now you have to work twice as hard to get rid of that fuzzy surface...counterproductive.