I had one of these removed today, just before they did it the nurse said oh you don't have a phone in your pocket do you? I said no and she said ok I'm just going to slip this under your bum cheek (I was sitting up and fully clothed) and it was like a thin grey thing about the size of a large mobile phone. Assume it was something electrical which is why she asked about the phone and I'm kicking myself that I didn't ask what it was. Does anyone know?