Renowned for its exceptional strength and versatility, FireLine thermally fused thread for jewelry-making by Berkley is the designer's choice for stringing and weaving projects. This popular jewelry-making thread resists abrasion and threads effortlessly. UV protection to withstand sunlight. Fits Wide-eye Needle and #12 English beading needles. Fireline is available in two colors, Crystal and Smoke Grey, in four sizes. We offer 4 lb. test with .005"/.12mm diameter, 6 lb. test with .006"/.15mm diameter, 8 lb. test with .007"/.17mm diameter, and 10 lb. test with .008"/.20mm diameter in a variety of spool lengths. We recommend using English beading needles for stringing and weaving with FireLine. Use #12 for 4 & 6 lb. test and #10 needles for larger diameters. To finish off your Fireline jewelry, thread burners such as The BeadSmith's Thread Zappers are a perfect solution because they enable you to pinpoint exactly where heat is applied. Simply tie a knot to finish your project, then burn the end. A small ball will form on the melted end that prevents the knot from untying.