Replacement filter made by Filter Everything and compatible with Nutone 23740-900. Dimensions measure 11-1/2 diameter x 3/32 thick. 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.