If you are wondering how this (sorry, its the truth) cheap chinese bit of electrical equip works, I am here to say that, yes, it works. I have 3 canister style scuba diving light systems that are around 20 years old and the batteries were no longer holding a charge. I took one apart and found 10 NiMH cells in series and glued together into a double high cylinder. New quality cells from batteryspace were $10 each. A new battery pack from the manufacturer (green-force) of the lights is 330 Euros plus shipping from Belgium and they no longer have a US distributor. So, for $300 for this spot welder and another 300 for 30 cells and some time I have replaced all the batteries and they now run the light heads for 7+ hours on a charge. The job was tedious and required skill and concentration, wear safety glasses, this thing can throw a hot spark if you get mis-aligned. My settings were 4P on pulse count and 5.5 on the dial and I hit each connection twice. See the pics. I practiced on some AA batteries and the old pack cells before I started on the expensive cells. Hot glue the cells together, pay careful attention to your series and parallel construction. I used a marker to mark + & - on the cells and also marked which were going to get the strips across them before I started welding. After you cut the nickel strips to length, flatten the ends. Be sure the nickel strips are exactly flat and positioned before you weld. I used the weld electrodes on the front of the unit as it lets you have both hands holding parts. Take your time. If you are doing a bunch of packs set up a jig to hold everything in alignment. Solder wires to the tabs before you weld them to the cells for the end points. I did not use the soldering iron attachment, as I have a weller already, so this review does not take that into account.