This is a 16" coil of 99.99% Pure Silver Wire in 10 Gauge (0.10 inch, 2.5 mm diameter). This silver wire coil is ideal for making rods for use in your home Colloidal Silver Generator. Our wire is 3rd-Party tested and verified to be TRUE 99.99% Silver, by UL Verification Services. True 99.99% silver is very hard to manufacture, and costly. Not all "reliable" silver wire mills honestly supply 99.99% silver. We've had first-hand experience with sub-par wire (less than 99.99% pure) being sent to us, and, after testing, we've had to turn away more than one manufacturer of wire that claimed 99.99%. We are as much concerned about the purity of the silver wire as you are. With this consideration, we take verification seriously, and all silver wire is shipped straight from the mill to Underwriter's Laboratory for testing, then to us. Please check out our website for more info on UL.A paper copy of both the Mill Certification of Assay (Chemical Analysis) and UL Verification Test Report is included with every order. Please Note: Since we have been verifying our silver wire by Underwriter's Laboratory (UL) for some time now, the UL Test Report that appears in the background of some listing images may or may not be the current Test Report. Please refer to the additional images that show the current UL Verification Test Report and Mill Certification. You will receive a half-size copy of each of those papers, which correlates with the batch of silver your order came from. A full-size copy of either report is available upon request.