1/4" NPT plastic airline fitting used as of 11/22/96 on All style Wind Doors and Clear Wind Seal Doors. On the Wind Door the size of the airline has also been changed from 1/4" to 3/8". Prior to 11/22/96 all style Wind Doors reference #1ELBOW-PL444. Used on: All style Wind Door cylinder assemblies Central Control Units for all Systems (Edge, Cloth Express Wash, Insta-Kleen, Pro Class, Enduro)