The First Chair CELLO Pad fits most sizes from 1/2, 3/4 to full 4/4 size instruments. Unique and needed, there is nothing else like it in the world! The AcoustaGrip First Chair Charcoal is a 2-layer CELLO Pad, offering ultimate comfort and protection against instrument damage from moisture (perspiration) while creating a fuller sound and enhanced feel of vibrations.