Solid and Hollow Silicon/Nonsilicon Polyester Staple Fiber (PSF) Item Types and Grades: 3Dx32mm/51mm/64mm: Type: Solid, Hollow Nonsilicon Grade: Recycle 6D/7Dx32mm/51mm/64mm/76mm: Type: Solid, Hollow Nonsilicon Grade: Recycle 6D/7Dx32mm/51mm/64mm/76mm: Type: Hollow Silicon Grade: Recycle 12D/15Dx32mm/51mm/64mm/76mm: Type: Solid, Hollow Nonsilicon Grade: Recycle 12D/15Dx32mm/51mm/64mm/76mm: Type: Hollow Silicon Grade: Recycle 25D/30Dx64mm: Type: Solid Grade: Recycle Usage: Ideal for a variety of applications, including: Nonwoven fabric Filling for mattresses, jackets, and comforters Spunbonded fabric Soft loft and hard padding Resin bonded fabric