That is for the 12GSA switch with an LED. The switch for the 650 is the same size, fits in the blank next to the fog lamp switch on the GSA and is quite cheap. I got the part number from a thread on ADVrider and the switch is now on the bike! BMW part number is 61311459306, it is up for on under pressure, centre off and down for on.
I use it to control the power to the intercom, bike to bike and GPS.