Set of 6 B&K 1" x 3/4" Black 90° Cast Iron Elbow Pipe Fittings Mueller 520-154BG Used - Good. Some surface rust and cosmetic wear present. 1" inlet to 3/4" outlet, NPT-to-NPT, Female-to-Female, 90-degree elbow, cast iron, model/model number 520-154BG, brand B&K (Mueller Industries). 6-unit quantity. Heavy-duty pipe elbows.