121-6003, Festo, Festo QSM Series Reducer Nipple, Push In 6 mm to Push In 4 mm, Tube-to-Tube Connection Style, 153329, Brand Festo, Pneumatic Fitting Type Reducer Nipple Festo QSM Series Reducer Nipple, Push In 6 mm to Push In 4 mm, Tube-to-Tube Connection Style, 153329