Spark gap for electrotherapy machine by Heller, Coudray and Co
Spark gap for electrotherapy machine by Heller, Coudray and Co, Paris, 1902
Electrotherapeutic machine, wooden case, with metal fittings, by Heller, Coudray and Co, Paris, 1902
Spark gap for electrotherapy machine by Heller, Coudray and Co, Paris, 1902
Interrupters for electrotherapy machine, wood and brass, by Gaiffe-Gallot, France, 1902
Narrow glass tube, originally mounted on the interrupter for electrotherapy machine
Transportable mahogamy and brass case with handles, for electrotherapy machine by Heller, Coudray and Co, Paris, 1902