This is your basic spool of lead free solder with a water soluble resin core. 0.031" gauge and 100 grams. This is a good spool for more advanced users that should last 6-12 months depending on how often you solder. If you are just beginning to solder, we recommend you order the leaded solder. Lead-free solder is a bit harder to use (does not flow as well). Mix: 99.3% Sn / 0.7% Cu https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2009-07-26 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2016-11-25 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2016-11-28 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2016-11-29 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2016-12-09 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2016-12-13 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2017-11-24 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2017-11-28 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2018-05-05 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2018-11-21 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2018-11-27 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2021-03-01 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2022-02-22 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2025-04-12 https://elecena.pl/product/872646/solder-lead-free-100-gram-spool 2025-04-14