K&N, Dry-Charger (rain sock) Rain protective sock, made from black polyester. This dry-charger is chemically treated to make it water repellent. Note: The Pre-Charger (dust sock) is no longer available but this Pre-Charger is identical to the Dry-Charger, is additionally chemically treated to be also water repellant. Fits: > 909617/8 909622/3 airchargers and other intake systems equipped with K&N 583034 filter element