A small aluminum tube that fits into the drain tube. It has a tab that wraps around the defrost heater, and transmits the heat from the defrost heater to the drain tube, therefore preventing it from freezeing and blocking during the defrost cycle. LG has no fix for it.Thier techs use a whirlpool fix, to do the job.
Its a problem shared by many makes of fridges. Poor insulation allows cold freezer air to come into contact with the drain tube, causeing to to block with ice, and leak down between the walls of the cabinet, onto the floor.