50VA Universal toroid core, open frame.
Universal toroid core, transformer. 50VA, open frame. Primary is 550 turns of #29 enameled copper wire wound around a 2.8" OD 1.5" high, tape wound, iron core. 120VAC Pri windings. PriRes=23-Ohms. Spec sheet #155 available. Similar to GenRad's old Variac or Superior's Powerstat.