A vacuum filter prevents dust from getting into the engine of the vacuum cleaner (engine filter). It is therefore very important to regularly clean or replace the filter. This will benefit the lifespan of your vacuum cleaner. The exhaust filter ensures a final filtration of the air, before it gets blown into the room again. This filter doesn't need to be replaced as often, because the vacuum bag should have caught most of the dust particles already.
All aspects of this sale (eg prompt delivery of invoice by email, website to keep track of shipping) were handled in a business-like and professional manner.
About the product:
The dustbags and filter I bought for my Bosch vacuum cleaner were exactly as described. Even though I lost a little money on the exchange rate from Euro to Australian dollars, the products were a better price on DustDeal than anywhere else!