... near ground about 10-15 cm,if the ring up ,up the palte and press the key ,then turn knod left a little.test ... you need not iron,just test the response to iron , if the ring up ,up the palte and press the key ,then turn knod left ... -ferrous metals to make the sound of a large decrease of the black metal to make the sound increased. The most accurate HZ-924 long ...