Another great Kester product. Commercially available, high-quality solder. My husband bought this because he wanted to switch to lead free solder and this lead free product is perfect. It contains 96% tin and 3% silver with rosin flux. He tried replacing the capacitor and transistor in an old FM tuner and said everything went smoothly and the switch to lead-free solder was easy and hassle-free. Overall a great product that he highly recommends.