25 Apr 2006, 20:24
That is the button coverplate [these are always made of brass, or some non-magnetic alloy, so as not to interfere with the transmission of the magnetic field between the button magnet and the reed switch]. It is 100% original. BTW, the part Time Computer used to correct an overly-sensitive switch is called a "high-mu shunt". The foil is a magnetically-conductive, high-iron/nickel alloy known as mu-metal [pronounced "mew"].