I found this on eBay:
http://www.ebay.com/itm/JBL-375-2440...kAAOSwIgNXwY-G
He also sells other formats too.
My self purchased felt (self adhesive) from the McMASTER-CARR (1/4" x 12" x 12") a brownish type of felt that works excellent Only drawback, I had to cut the pattern my self , but its OK with a sharp scissor......