Made of stainless steel, it is not sticking, use the needle penetration component pin, heated with a soldering iron, a slight rotation to the component lead and copper foil separation Used for hardware engineer to desolder the Electronic components(e.g. DIP components)from PCB , Because the needle is used with special stainless steel , the needle will not be pasted Flux Size:0.8 1.0 1.2 1.4 1.6 1.8 2.0mm There may be some stains on the box, please don't mind.