... , 500g/roll 4.Sn-8Zn-3Bi , lead free type tin solder details :Shape&Tolerance:WireAppearance:Surface bright , no dirtWeight ... :Net weight about 1KG/rollPacking:10 rolls/boxApplication:For electronic components, household electrical appliances, transformersWelding ... 37. The first number always represents the tin content; the higher the tin content, the lower the melting point. ...