Gently Used Rachel Zoe Open Front Soft Tan/Beige Chenille Sweater/Cardigan with Side Pockets. Made of nylon, viscose & pbt, hand wash only. Very soft, beige/tan size medium. *PBT stands for Polybutylene Terephthalate, a type of strong, elastic, and durable polyester yarn used in fabrics. PBT yarn is known for its excellent stretch and recovery, breathability and quick-drying properties, making it a good choice for comfortable and long-lasting knitwear.