Unless someone has one used to offer, the part is pretty much unobtainium.
You may try to make one via 3 power resistors 50w 5.3k +500 + 500, but the 5.3k in large sizes seem to be hard to find, closest I have found so far, is 5.6k, this may be close enough in this case.
HSA505K6J
THS50500RJ