The gauge refers to the thickness of the wiring in the jumper cables. Thicker wire carries more power, allowing you to jump-start larger batteries. A low number means thicker wire. Larger vehicles need cables designated as 2 or 4-gauge. An average set of jumper cables should have wire that is 6 or 8 gauge. Cheaper jumper cables usually have 10 or 12 gauge. Note that cheap cables may not last long or work well for all types of jobs.