This is a replacement bag for your Kirby vacuum cleaner. The bag reduces common household dust, pollen, and other particles. The electrostatically charged material traps particle matter after it is picked up from your floor. This keeps dirt and dust inside your Kirby vacuum bag and not in the air around your home. This is universal style bag filter fits both f-style and twist-style Kirby models.To ensure your vacuum maintains maximum performance, replace filter bags before dirt reaches the "Full" line.