Heavy duty, copper-plated clamps. 100 amp load capacity. 0-16 volt range. Load safety switch prevents arcing. Heavy duty, chrome plated, ventilated steel case Tests batteries on or off the car in just 10 seconds. Works on both 6V and 12V batteries. Convenient, portable size and easy to read scales. Features ceramic insulators. Determines state of charge, cranking, and charging volts. Determines good/bad status. Has extra large display with zero adjust.