The Selective/Stakeless Current Clamp Kit is used in combination with the Fluke 1623-2 and 1625-2 to perform selective and electrodeless measurements. Selective measurement involves using one current clamp with a number of ground stakes to generate ground loop resistance values for one ground electrode. With the electrodeless measurement, both supplied current clamps are used to measure the earth loop resistance without earth electrodes. Both measuring methods have the advantage that measurements can be taken without interrupting the earthing system! Safer and faster. Already included in Fluke kits 1623-2 and 1625-2. Both current clamps have an inside diameter of 50.8 mm (2 inches).