We have 9 Carbon Stationary Pads from Vintage Music Store lot.  They are 8 1/2" x 5 1/2".  The pad is carbonized with a top white sheet and back yellow where the writing get's transferred to.  These are from an old music store which closed. I believe they date from the 1970's - 1980's.

Carbon Stationary Music Lesson Stationary Vintage 9 pads