WINRES-20B BLUE is designed using advanced engineering technology to measure the winding resistance of transformers. WINRES-20B BLUE can measure current, voltage, power transformer windings and shunt resistors. Applying up to 20 A DC allows WINRES-20B BLUE to measure the winding resistance of transformers quick and precise. https://www.hightest.co.uk/product-cat/winding-resistance-tester/