Lisle offers the 24V Heavy Duty Circuit Tester (No. 27430) which quickly tests voltage on any circuit up to 28V. This tester includes a heavy duty probe, cord and clamp. The probe is insulated with high-visibility shrink tubing to prevent the possibility of shorting the side of the probe to other components. Comes with a strain relief spring on the cord. To use, simply connect heavy duty clamp to a ground source. Tester will light to show power.