In all sizes of the LF3000 fittings, except 3/16, the push button is an integral part of the design which makes it non-removable, and comes standard in black. For identification of the circuits, colored caps (p/n 3110) fit over the black push button.
On the 3/16 sizes, the buttons are removable and can be replaced with a button of another color (p/n 3330).
CAUTION: These fitting systems are not D.O.T. approved. Do not use for air brake connections.