Fine Mesh: The mesh and grid spacing of this tent vent cover is small enough to block most particulate matter and small pollutants It does not affect ventilation or enter the internal environment, thus protecting the plants and keeping them in good condition Material: The pipe filter cover is made of waterproof and reusable Oxford cloth Easy to use and clean: Simply place the particle filter cover over the vent and secure with the drawstring and latch So it is easy to replace, hand washable or machine washable Multiple Uses: This tent vent cover can be used in grow tents with inline fans and air ducts; it can also prevent the tent fabric from shrinking due to the difference in air pressure inside and outside the tent Colour:Black Material:Oxford cloth Size:6 Inches Package Contents: 4 x Insect net Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.