FlameTech 6290-3 Cutting Tip, Acetylene, Size 3 100% Flame Tested in the USA for Great Performance Copper Shells Machined from Solid Bar Stock(Not Tubing)Last up to 3 Times Longer Extra Heavy Duty Shell Tip takes More Abuse Larger diameter decreases preheat time and maintains the cut on painted or rusty surfaces Course "V" Splines allow better flow of gas, resist clogs and are easier to clean