0.15" (4 mm) of exposed metal at the tip Probe extenders fit between modular test leads and test probes, increasing the distance between you and a live circuit by 8" (20.5 cm) TP238 and TL224 conform to safety standard IEC 1010-2-031, maximum 1000 V CAT III, 600 V CAT IV, Pollution Degree 2, 10 A Probe extenders conform to safety standard IEC 1010-2-031, maximum 1000 V CAT III, Pollution Degree 2, 10 A