The tightly woven synthetic HEPA fibers in this filter will help prevent mold, bacteria, and insects from entering your greenhouse. The HEPA fibers block out most airborne particles yet allows air to flow through with little restriction. The filter is also washable for extended efficiency. Installation: Attach your Organic Air HEPA filter to your fan or blower by sliding the rubber collar over the inlet or outlet side. Secure the filter by using the clamp provided, tighten clamp with screwdriver. Remove and wash filter when needed with water hose. Filter should be replaced every year under moderate use. Keeping the filter clean will ensure efficiency. 8" fan recommended for use with 10" fan.