Dyson 911236-01 DC17 Filter
This is the washable filter for all Dyson DC17 models. This will fit models like the Dyson DC17 Animal, as well as the Dyson DC17 Asthma and Allergy. This filter is located directly underneath of the dust bin when it has been removed from the vacuum. You can find the filter by finding where the air is being exhausted. This filter should be replaced at least every 3 months. If you notice that your Dyson has lost some of the suction since you've had it, cleaning the filter should be the first place to start.
Genuine Dyson Part 911236-01.