I really did not understand this product but then when I used it and realized that it cleans out the vacuum canister without getting the dust and dirt back out into the air it was wonderful. My kids suffer from allergies and asthma and when I would vacuum or clean out the canister I would do it outside now I can do it right inside and nothing gets out this is a great product. It cleans out the canister fast inefficient it is a wonderful tool to go with the vacuum cleaner.