Using these Klein test leads is easy. First, check that your meter has banana - type input jacks. Then, insert the banana plugs of the test leads into the input jacks of your meter. Next, use the heavy - duty alligator clips to attach to the wires or conductors you want to test. This is great for insulation resistance testing. When using, make sure not to exceed the CAT III 1000V/CAT IV 600V safety rating. Avoid using the leads in wet or extremely hot environments. After use, store the test leads in a dry and cool place. If the alligator clips get dirty, you can gently clean them with a dry cloth. Keep the test leads away from sharp objects to prevent damage to the wire insulation.