Hoover Type R30 Filtration Replacment System 4010100 For all Hoover Canister cleaners using Type R30 bags. Includes 5 bags, 1 secondary filter, and 1 final filter. It is recommended that all three filters be replaced after every 5 vacuum bags. These filters, 1 secondary and 1 final filter, combine with the filter bag to create a 4 layer filtration system for your canister vacuum.