Replacement carbon filter made by Filter Everything and compatible with Broan / Nutone 99010113. Sold as a 1-Pack. Our filters are manuctured to meet or exceed OEM quality and are fully compatible with the name brand (OEM) model. Aluminum filters should be cleaned every 60-90 days; carbon filters should be replaced every 6-9 months. Proudly packed and shipped from our facility near Cleveland, OH.