WHAT A PIECE OF JUNK! I puchased it in the afternoon and returned that evening, after reading the instructions carefully I tried it out and the tip literally crumbled before my eyes. After you get beyond the arching, sparking and crumbling you'll be surprised at how the solder hasn't melted nor have the wires or joint heated up to operating temp "melting point".
What a hunk of junk, I literally would'nt accept one if it were giving to me, save your money.