High Quality Ventilation Filter: Made of needle punched cotton filter fabric. Special electrostatic filtration captures small particles, reducing dust in your home. They also prevent unwanted objects from entering your home. Great Value for Money: Each pack comes with 200cm x 100cm filter cotton and 300cm non-marking double-sided installation tape. It can cover more than 36 standard exhaust ports. Cost-effectively covers larger non-standard air vents. Flexible DIY Design: Compatible with all sizes of vents, air vents and grilles. Cut to fit any size vent. This versatile design makes it easy to cover or install behind non-standard sized vents and for DIY projects. Easy to Use: Simply stick the mounting strip to the outside of the vent and stick it on. Easily replace dirty filters without removing the vent. Easy to apply and replace without restricting airflow.