It is a very soft conjugated extra slick hollow poly that is smooth and light after being processed on our state of the art equipment that opens the fiber close to 100%. This fiber is extra smooth and light. Feel: very soft, very bouncy, resilient, smooth and durable. PERMA SOFT Polyester Travel Pillows are filled with Perma Soft hypoallergenic fiber. The cover is a 220 thread count, white down proof ticking.