The duplex test lead measures both current and resistance when taking four-wire resistance measurements, which are more accurate than two-wire resistance measurements and allow low resistance values to be detected. The helical spring-point hand spikes compress and rotate to make contact with a conductor. There is 0.4" between the current and the potential probe tips on the duplex hand spikes.

The duplex test lead measures both current and resistance when taking four-wire resistance measurements, which are more accurate than two-wire resistance measurements and allow low resistance values to be detected. The helical spring-point hand spikes compress and rotate to make contact with a conductor. There is 0.4" between the current and the potential probe tips on the duplex hand spikes.