I can't believe how good the ZD-21 soldering iron and the tips it uses turned out to be, despite their very low price. The soldering iron reaches a temperature of around 330 degrees (measured), but the tips don't struggle at all, showing no signs of wear or degradation. They are able to hold a large amount of solder on them and perform more demanding soldering tasks than you would expect. It outperforms the much more expensive Antex XS25 (which I have had for years) and when it comes to the tips, they wear noticeably faster even though they work at lower temperatures