Vintage Black Bakelite Rogan Bros. early radio/communication control knob w/ indicator stripe. Item is in good condition.   D Slot in a 1/4-inch sleeve with set screw. 1 3/4 in. diameter at the base, 1 1/4 in. at the top, 3/4 in. tall with a slight crowned top. Used on early radio and communication, test, commercial / industrial electronics.