C-track bumper, Märklin 24978, but with flicker-free, warm white LED.

With antiparallel switched, warm white LED.
Flicker-free operation directly on the traction current!

The current consumption is less than 0.5 mA, thus negligible even when using several buffer stops.
The power is supplied directly from the track: no further power supply is necessary.

The light colour and luminosity are adapted to the newer Märklin C-track turnout lanterns.