I just wanted to let you know that the two retrofit kits with OXYSAVER CANNULAS worked very well in the flight operations I performed within the past two weeks. I am a pilot in command of an aeromedical helicopter in the Rocky Mountains and this cannula was so comfortable, I didn’t even feel it as I was flying! Other medical cannulas I’ve used were quite uncomfortable after a short period. I used the cannula between 10,000 and 13,500 feet MSL for time periods of ten to seventy five minutes. Based on my recent usage, I would recommend the OXYSAVER CANNULAS for those flight operations allowing their use, especially those when wearing of a headset and mike boom is required.