Product review (5 stars): OEM part to repair my dishwasher
This is the lower spray bar for my Samsung DMT300FRB dishwasher. My lower spray bar would not stay snapped in to the holder. If your spray bar does not stay snapped in to the holder you will need to replace both the spray bar and the holder. The holder is:

Samsung Holder - Nozzle L Dmr Part # Dd61-00241A

You will need to unscrew the 13 (or so) screws holding the screen down to access the holder. Replace the holder and replace the 13 screws. Pop the new spraybar down into the holder and you are done!

I replaced both of them in about 5 minutes and the dishwasher is again washing fine.

UPDATE:
Samsung engineers are masters at the art of planned obsolescence! About a week after replacing the lower spraybar the top spray bar started popping out of its socket. So I ordered the upper spraybar and it's holder. Do yourself a favor and order all these parts at the same time, it will save you a lot of manual dish washing!