Fluke Corp.'s TL175 TwistGuard Test Leads, include a manually adjustable test tip guard for use in different measurement environments. By simply twisting the test lead the user can change the exposed probe tip length from 4/25" (4 mm) to 3/4" (19 mm). These test leads have earned CAT II, CAT III and CAT IV safety ratings, and also come with WearGuard insulation. Each test lead is covered by two layers of silicone insulation: red or black on the outside, and white on the inside.