I have to aggree with the above poster. Tubing is not all the same and neither are the connectors. All of my IV tubing is transparent and all of my BP cuff tubing is either black or opaque white and about twice the diameter of my IV tubing. I got out a IV cath and tried to hook it up to my BP machine. Now I was able to MAKE it fit but it was obviously not intened to fit and did not fit well. I did the same with a nasal canula/non rebreather mask and tried connecting them to an IV line, it is possible to make them connect but again it didn't fit well and was definatly not intended to. What I take away from this is a lesson in how badly fatigue can impare your judgment.