This will fit on your F4 intake boots. Use when servicing your bike to prevent anything from entering the intake tract. This snaps right in. The hole on the tab makes it easy to grab the plug for removal. This also includes a GAS TANK cap that fits the bottom of the gas tank where the fuel pump assembly is attached. You will need an O-ring to seal the opening properly. I have personally used this to de-rust the interior using muriatic acid.