FireLine is a pre-waxed, braided cord consisting of gel-spun polyethylene which is known as the strongest fiber, per diameter, ever created. It has an unbelievably high tensile strength and popular for bead weaving and bead embroidery. The 4 & 6 lb. tests will fit a #10-#12 English beading needle. We highly recommend Fiskars 5 inch Precision Scissors for cutting this thread as it can dull ordinary scissors.