If your fly is of normal height see small, no worries. However, I have needed to zap 5 see some big flies 6 times (those that make a sound not possible when they are caught between the window and the curtain) I suddenly think twice before trying to zap the wasp that tournicotte around the table in summer ... we miss the more angry!
Please note also, even off static electricity remains therefore I advise against touching the grill, otherwise it's bed :)