This invention improves aspects critical to the reflector making process currently in practice. 1:1, a silanol-functional polydiorganosiloxane gum, and a crosslinker exhibits high tack and high lap shear strength. The opposing field sensing element is small and compact, and immune to vertical axis flutter and disturbances of the ferromagnetic cable being inspected. The battery isolation circuitry senses voltage at the output node and variably restricts current to the battery when the voltage is below a minimum voltage value by operationally controlling the semiconductor switch as current passes through it.