Western Enterprises - Vn Series Hvac Purging Systems Vn Series Hvac Purging Systems - 22 Cf With Carr: 312-Vn-122C - vn series hvac purging systems - 22 cf with carr Gas Type - Nitrogen Fill Port - CGA 580 Outlet Size - 1/4 in (NPT) Includes - Empty Aluminum Cylinder, Regulator, VC-55 Carrier Cylinder Cap. - 22 Cu. Ft.