The Hygieia Pre-Motor Filter for Dyson DC35, DC43H, DC44 and DC45 found behind the dust canister of your Dyson vacuum cleaner is an essential part of keeping your cleaner running smoothly. This filter acts as a barrier to prevent large dust particles from entering the motor, which can cause damage and decrease the vacuum's performance. To ensure optimal performance, it is important to clean and replace the filter regularly. A dirty or warn filter can significantly reduce suction power and decrease battery life, so it is important to check the filter regularly and replace it when necessary. As a result, you'll get the best performance out of your Dyson vacuum and enjoy a longer battery life.