Take your time and do a practice one. This tool gave me perfect crimps on 1/0 gauge copper lugs. I go real slow to just start the crimp because u really need 3 hands. After it's perfectly aligned then u can finish the crimp. Don’t over pump it, follow the direction. Add your heat shrink tubing before u crimp. I really like this tool. Somebody posted the sae to metric conversion in the reviews.