This is located on the side of the pressure switch. If your valve is attached to your switch by inserting through a hole on the side bracket or through the bottom, then this is your style. Can be used with copper or nylon unloader lines. Order this if your valve is broken. If this valve leaks continuously after it shuts off, then don't order this, order a check valve on the check valve page. It backfeeds this valve when defective giving a false sign that this needs to be replaced.