K&N's DryCharger material is made from durable polyester pre-treated with a proprietary hydrophobic process. It can be used to make a filter wrap for sizes that are not currently available. This material is designed to prevent splashes of water or mud from saturating your K&N air filter. It will also stop small dirt particles while adding little restriction to the airflow of the filter. DryCharger material is a water repellent. It is not water proof. Depending on conditions and usage the water repellent treatment is good for 1 to 2 years.