dont know the brand.
But it seems to me that it is a 512KB memory card.. With such low capacity i almost sure, its some kind of `back fill card` specially for the IBM XT computer with you have the older gen 64K -256KB motherboard.. So you could back fill it to 640KB of conventional memory.
I also have seen that card on marktplaats. But skipped it, because i dont have a XT class IBM with a lower capacity memory on the motherboard.