Any kite line made from Spectra fibers will lose strength when knotted. Depending on the knot, your kite lines strength can be reduced by up to %60. An example would be if you had 100 lb. tensile strength spectra line a knot could actually break with only 40 pounds of pull. Sleeving your kite line at any knot can actually make your kites line up to %50 stronger that if you don't sleeve them. This sleeving kit is a fast, and easy way to protect your kite line from breakage. This sleeving kit is meant for use with stunt kites and single line kites. The kit includes instructions, one wire sleever, and two pairs of 12" nylon sleeving. Made in China by New Tech Kites.