The K&N Drycharger® is a silicone-treated, polyester wrap that is made to cover K&N Air Filters or Personal Watercraft Flame Arrestors. These Drychargers, which are similar to the K&N Prechargers, contain uniform micron-sized openings that allow high airflow. Yet, due to the Drychargers silicone-treated polyester wrap, the amount of water that reaches the air filter or flame arrestor is limited. Features: This product wraps your air filter with an additional pre-filter. Extends service interval of your K&N filter. Durable silicone-treated polyester material with stitched elastic openings. Water repellent treatment typically lasts 1 to 2 years. Specifications: Mate rial: Silicone Treated Polyester Height: 54mm Base Inside Diameter: 159mm Top Inside Diameter: 140mm