It's a Welfix Desoldering Wick. Desoldering wick is made of copper threads that have been braided together. Desoldering Wick works well for faster and cleaner desoldering. To remove the soldered joint, use it in conjunction with a heated soldering iron. Unwind about 5 cm length of the Desoldering wick and interphase its tip between the soldered joint and the heated soldering Iron (of at least 25 watts ratting) solder will melt and Desoldering wick will suck it up immediately.
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