I don't normally write bad reviews but I had to. I have received this product. Robinair is a good brand in the HVAC industry. At least it was. I've used them for work and the first time the blue suction hose wasn't fully pressing against the Schrader core on AC units I've worked on. I've tried them on many different devices and brands. I thought I just had a bad tube so I quickly got a replacement from Revain. The second set had a bad yellow-blue tube. I figured they had a bad batch or the manufacturer would have to go back to the drawing board.