Heating Unit. Material: leather, metal, textile, plastic. Size: 19" diameter x 1 1/4" thick. Description: brown leather - ring shaped - interior magnetic unit encased in leather ring - black cotton covered electrical cord, metal prongs extend from brown plastic cap on one end, black and red plastic toggle switch encased in brown plastic unit on other end close to pad unit - silver colored metal spring near unit provides flexibility to cord. Stamped on embedded metal disk: "Electro Coil Mfg. By The I. E. Co. , S.F., Cal., 40 Watts, 110-120 V., A.C."