These are replacement bags to fit the Nutone central vac. See Pic. They are micron filtration bags. 3 bags in one package. You are getting 1 package. NuTone 391 Series Filter Bags fit 350, CV-350, CV-352, CV-353, CV-400, CV-450, CV-550, CV-553, CV-570, CV-653, CV-750,CV-850


part # 391-8

Flo Master C650 Filter Bag. Astrovac , Beam  (167, 3067, BU165, V165 models, and 110025 and 110056 bags), Broan , Dyclovac , Centra clean Home Environmental System, Dynavac , Easyflo Eureka ,  Filteraire, Frigidaire , Galaxie, Heatilator units (except model 4000), Housekeeper by Rittenhouse, Husky , Miami Carey,  Nutone  (391, 391C, and 44186 bags for CV350, CV352, CV353, CV400, CV450, CV450W, CV653, CV750 and CV850),  Power Star , Singer , smart , Soluvac, Star , Vacuflo  200 (bag 6528), Filter-Aire #90610,