1930s Portable Induction Test Meter. Material: plastic, metal, glass. Size: 6" W. x 8 3/4" H. x 7 1/2" D. Description: black metal box; silver latch on front; lid at top; metal plate on outside of box: "Portable Watthour Meter Standard, No. 15358215, Type IB-8, Amp. 1-5-10-50-100, Volts 115-230, Cyc. 60, General Electric Co., USA"; Portable Induction Test Meter instructions listed inside top lid; note stating that this unit is 1/4% slow at 20 revolutions; nine black knobs on top; four white buttons "10A, 1A, 230, 115"; glass covered circular gauge in center; "Revolutions, General Electric"; dial numbered 0-9; two smaller dials below; 100 and 10 numbered 0-9; two open ports on right side of box; silver metal knob on each side of box.