So, with every airless tip, there’s a tip half-moon retaining washer. It’s half-moon because it’s cutting a half-moon shape that goes into the back of the tip base.
So, the end of the tip itself is a tool to place the half-moon washer in the back of the tip base.
So, what we have to make sure is that because that is round, the half-moon faces into the tip itself. The tip has a cam on it which pushes in the front, pushes round the back.
What you will find when you put that backing washer in, you have to hold it with your finger to ensure it stays in place before you screw it onto the gun.