Sleepsia 18 x 18 Throw Pillow Inserts (Set of 2) - Fluffy Polyester Down Alternative Lightweight Bed and Couch Pillows - 18 Inch Square Sofa Decorative Pillow Inserts - White Couch Pillow. Pillow Inserts with Premium Material: best throw Pillow inserts filled with Down Alternative 100% Premium Microfiber fill provides not only softness, also high resiliency with durability.