Hello Gary,
Our fittings fit on the OD12mm hard tube. So if the 12mm glass tubes for water cooling (Pyrex or Borosilicate) is exactly OD12mm, it works. We advise you to choose this one BP-EMLA12-4P. It is easier to use. Any questions, feel free to contact us.
https://shop.bitspower.com/index.php?route=product/product&product_id=7695