The advantages of 3 Stage Filtration The Big Green Complete deep cleaner and canister vacuum has 3 stage filtration. This means the dirt, debris and air the vacuum suctions up goes through a sophisticated filtration process before releasing any air back into your home. The water filtration stage captures and sinks large particles, including dirt, hair and crumbs. Smaller particles are captured by the secondary filter, insuring that the vacuum captures all the dirt and dust you vacuum up. Finally, the Multi-Layer Post-Motor Filter cleans and filters the air passing through it. Big Green Complete Deep Cleaner & Bagless Vacuum Br Green 7700