Tweco 1110-1104 Fabricator 140/180/190 11-45 MIG Gun Contact Tip for .045 Wire Diameter (5-Pack) Machined from a copper alloy tubing providing a consistent and smooth inside diameter surface Thick-walled diffuser design acts as "heat sink" and conducts heat away from the arc source Easy identification - each contact tip is marked showing the part number and wire diameter Increased surface contact between contact tip/diffuser for better electrical conductivity Connects easily - just twist it and it locks in place with no threads