Wehrli Universal Outerwear Air Filter Cover (Use w/WCF Air Filters)Water Resistant: Filter cover Hydrophobic treatment helps repel moisture and protect against water entering the engine due to puddle splash or heavy rainstorms. Although our Pre Filters are proven to be extremely effective in repelling water, please keep in mind they are NOT WATER PROOF. If submerged, your intake can hold or pass water. This treatment will last for six months to one year, depending on use and conditions. As a general guideline we