Product review (5 stars): Correct part to fix broken plastic cam, which is not available separately
This was the correct part to repair my Samsung RSG257AARS left lower hinge assembly which had a cracked lower cam (the black plastic ring bolted to the hinge).  This plastic cam is not available as a separate part based on my research.  Installation took about 45 minutes start-to-finish.  The upper cam ring which attaches to the door IS available separately.  I did not need this.  Consult your user's manual for illustrations on removing the freezer door, particularly the water line clamps.  User's manuals are available online as pdf's if yours is lost.  When the job is finished and you reattach the water lines, Samsung suggests installing two red clips to insure a tight clamp.  I still had my clips in a plastic baggie.  I don't think they are initially installed at the factory, but are recommended to be used after the water lines have been disconnected the first time.  Amazon's price on this part was competitive. That it included 2-day shipping and Sunday delivery was unbeatable!  This job is easier with a helper to prevent damage to the door during removal/reinstall.  The door itself is very light provided you empty the shelves and detach the ice bucket (both of which you should do).