Shrinkfast 998 Heat Gun Spring -Part# 21
The Shrinkfast 998 Heat Gun Spring (Part# 21 on the diagram) is coils around the fuel Line (part #9) and rests just above the Valve Assembly (part #22). The Spring is responsible for returning the Safety (part #20) to its resting position when the Trigger/Igniter Assembly (part #17/18) is released.