Features and Benefits:•Reduces diameter of air flow helps prevent warping of surrounding plastic.This nozzle fits the Steinel Hot Air Welder and reduces the diameter of air flow to 9 mm. This piece is neccesary if you are going to use the speed tip with the welder. This "may" fit your existing heat gun. If the nozzle on your heat gun is 1.25 inches in diameter, it may fit.