126 810 00 12 plus a 4 digit code depending on the colour. Looks like $13 each.
Make sure that you remove the fuse before replacing as it is very easy for it to spin and short out.
I usually pick up a few spares at the wrecker as they are used in W123, 124, 126 and 201 cars so lots around. The cover for the screw however rarely survives. Never been charged for one yet.