A nickel-chromium-molybdenum-copper alloy that is resistant to sulfuric acid and wet process phosphoric acid contains in weight percent 30. The host controller includes a buffer memory and has a function of reading the data from the device into the buffer memory. The heart and contrast agent are imaged to provide a visual indication of the location of the structures of the heart. A user interface operatively associated with the signal processing system produces a user-discernable output indicative of the probabilistic determination of the classification of the ferromagnetic object within a sensing area. The golf club head preferably has a moment of inertia about the Izz axis through the center of gravity of the golf club head greater than 4000 grams-centimeters squared, and a moment of inertia about the Ixx axis through the center of gravity of the golf club head greater than 3000 grams-centimeters squared.