Sorry I have to disagree they are a royal pain in the butt to replace , and I wouldn't recommend a PO to anyone because of this . At least with and IWC BP you can squeeze the tube to help it a bit but with PO you have to buy a new tube and I had to get a Gen Crown and Tube and these don't fit the rep and it was a very long and expensive journey to get fixed . Though I am sure there are many happy PO wearer's out there , there are many like the OP and Myself who had issues after just a few days of ownership and think the UPO tubes are a POS