A 2-in-1 Tester that Tests Circuits up to 12 Volts and Works as a Jumper Wire for Power or Ground. Heavy-duty circuit tester for checking low voltage up to 12 volts. By depressing the red button the tester becomes a jumper for powering electrical components or a ground. The probe, handle, cord and clamp are reinforced for durability. Comes with a strain relief spring on the cord. 28440 Replacement Bulb