Modifyed soldering iron. Bought on eBay and the iron is a 60 watt iron with adjustment on the output heat. The iron shoetip is from another soldering iron also bought on eBay, but that iron did not delivered the propper heat. The iron fot is the cut down to 25mm with and the tickness under the fot then grined down about 5 mm so the heat transfer faster. Seams to work fine under my third packraft build.