I have nearly always had a bad skin reaction with G3 and G4 sensors. For me, the oval tapes are fine, it is just the adhesive flap that goes underneath the transmitter. Initially, Medtronic gave me a large box of IV3000 and told me to insert the sensor through them. Quite apart from the fact that the IV3000 instructions warn you against attaching other adhesives, this tended to lead to sensor failure. Some years ago, I came to the conclusion that the value of the sensors outweighed the irritation, occasional bleeding, and time taken for the skin to recover. I look forward to the long-promised Simplera Sync sensors. At least they are smaller. Medtronic and the hospital pump clinic have no idea when they will arrive. Hoping it is within my lifetime!