Make of high-strength stainless steel, rustproof, smooth surfaces. round hole will not frays your fishing line. These fishing line sinkers slides hook shanks connectors can bear more tension, providing accurate placement when casting line in deeply water. none leakage around the hole, easy to thread. The high stretch rolling swivels allows for twisting without tangling and harming your fishing line. Easy to use: Put the fishing line through round hole and tie the fishing line sinkers slide to another swivels. The fishing line sinkers slider making it easy to throw line into the water when you fishing, help you sink the fish line deeply, carry more tension and accurate location when casting line deeply in water.