rods 2.5 3.2 4.0mm as stated thickness of metal for size of rods.6013s are good but u can end up with holes in weld.7018s are low his to me far beter rods no holes and strong weld to.take ur time and get ur amps set right.used to be employed as a welder some sayd a may have slept with one lol.good settings good welds