Genuine Kjellberg F4030 swirl gas cap (3.0 mm bore) for mechanised plasma cutting at 90 A to 200 A with oxygen or compressed air. Fitted over the nozzle, it guides the swirl gas around the plasma arc to keep the arc stable and tightly focused, while protecting the nozzle from spatter and heat during piercing and cutting. A cap in good condition is essential for square, clean cut edges and consistent consumable life.