The gun is where the pressurized water is expelled from, once the trigger is pulled. There are different types of guns, from weeping guns to open guns. Some have the inlet in the rear of the gun, some are on the front of the gun. Some guns have the lance already attached to it and are sold as an assembly, others have a thread on the end that allows one to attach a separately lance or extension. Always choose the right gun for your unit, as each one will have a specific pressure and flow rating.
This item fits the following models:
3-Nailer Combo Kit w/ Accessories
3-Nailer Combo Kit
1/4" x 50 Ft Noodle Air Hose with Coupler and Plug