Pollen Guard 36 in. X 84 in. Charcoal Polyester Insect-Mosquito-Zancudo Screen for Windows-Sliding Doors-Vents polyester yarn Imported Specially designed to block up to 50% more particles than standard fiberglass insect screen This unique knit design allows air to flow through while blocking pollen, dust and other particles. Pollen Guard is manufactured using polyester yarn. Manufactured in Germany using strict quality control