DO NOT BUY THIS FILTER TO REPLACE THE HOOVER HEPA FILTER! The Hoover Windtunnel T-Series HEPA rewind filter I was looking to replace was a well-matched element that ultrafilters dust and debris sucked into a vacuum. A filter manufactured by Crucial Vacuum DOES NOT CONFORM to this part.1. The item does not look like a Hoover brand HEPA filter.2. The item HAS NO PERMANENT CONNECTION to the I3 vacuum. The front of the replacement filter has a gap/full opening that allows air to flow through the filter and out the front of the vacuum, allowing the air exiting the vacuum to blow dust and dirt off the floor in front of the filter. vacuum away from the vacuum while using the vacuum to vacuum. In order to use this replacement filter to collect dust and dirt from the floor with my vacuum cleaner, I have to pull the vacuum cleaner back because if I push the vacuum cleaner forward all the dust and dirt will fly around the room. 4. FINALLY, without a fully closed filter, the noise level is four times higher than with a Hoover brand filter. I figured I was saving money by buying this $7 Crucial vacuum filter instead of the $19 branded part. It was a big mistake. It takes 3 times longer to clean the same spot and I can guarantee the dust is now being blown all over my furniture due to a design flaw / gap in the replacement filter. If it didn't cost so much to return filters I would do it in a heartbeat.