Solderex premium audio grade 4% silver solder provides superior lower resistance connections due to the increased conductivity of the 4% Silver added. 2% premium grade no clean flux is added to allow for superior flow at low temps. The special halogen free flux is safe on even the most delicate precious metals. Used by some of the most discriminating audio manufacturers in the world. Make your project come alive with SolderEx audio grade silver solder and insure long term reliability. The 1.0mm diameter is good for small to larger sized solder joints and connections. RoHS compliant