Tech Team's positive / negative (+/-) 12-inch Diesel Jumper Cable is designed to series connect two 12-volt top terminal batteries for 24 volts output for diesel engines which require 24 volts and high current for starting. Both ends have military grade lead top post terminals, the positive is 19mm and the negative 17mm. When it comes to battery cables the LOWER the AWG number the HIGHER the current carrying capacity. Tech Team's #2 AWG cables carry far more current than other #4 AWG, #5 AWG, or #6 AWG (do not even think about #8 AWG) cables. This means less heat buildup and less voltage / amperage drop which prolongs the life of starters, inverters, motors, and other connected electrically powered devices. Includes one (1) black 12 inch #2 AWG 100% copper stranded wire battery jumper cable with one lead top post positive (19mm) terminal and one negative (17mm) terminal.