$70 is good price for any model Fusion Air Purge applicator pistol which only recently was being use by top spray foam insulation co in Toronto but upgrade to the heated hose make this attachment obsolete
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Inside this handle, when the trigger is pulled , two components mix: Isocyanate and Resin combine in mid air and a chemical reaction to make foam by the time it hits the wall
Read more about spray foam insulation process here?
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The gun is in good condition and has many years of life remaining; you cant break these things. $70 OBO