O2 Union 6 to 4 mm I, one-touch€ 7,00 One-Touch (Push-to-Connect), 4 x 6 mm, I union. Only 2 left in stock (can be backordered) O2 Union 6 to 4 mm I, one-touch quantity Add to basket Categories: Adapters & parts, Oxygen Description Description O2 Union 4 x 6 mm I, one-touch. To connect the smaller 4 mm air tube to the wider 6 mm tube. Related products Oxygen/Adapters & partsO2 mounting bracket for 10 cm (EU) cylinders € 34,50 Add to basket Oxygen/Oxygen cylindersAluminium cylinder – 2 liter € 159,00 – € 179,00 Select options Oxygen/Adapters & parts/Mountain High EDSMH Euro DIN 477-9 Pressure regulator (2G) € 329,00 Add to basket