Automotive Fuse Tester - RX1967 - Laser If the fuse is 'good' the LED illuminates. If the fuse needs replacing then the reverse of the tester is used to unclip and remove the fuse. The adjustable pins allows it to be used on mini/standard and maxi automotive fuses. The battery is DC15V and can last more than 100,000 hours with LED bulb. Ideal glove box tool. Space saver.