The primary filter is an important component to your vacuum. It is essential in aiding the filtration and suction of your ash vacuum, and prevents debris from entering its motor and other essential parts of the vacuum cleaner. If you do not use a vacuum filter, the motor will undoubtedly fail or fail prematurely. The Love-less Ash 9F66 Ash Vacuum Cleaner Primary Filter is the absolute necessity for your ash vacuum. It is placed outside of your ash vacuum's motor and insures that ash does not retreat into your living space. Because of its fiberglass construction, the filter will not combust if warm ash or a spark occurs in the vacuum. It can withstand temperatures up to 1200 degrees. To be certain that your ash vacuum investment is worth every cent and dollar, invest in the Love-less Ash 9F66 Ash Vacuum Cleaner Primary Filter.