1) Cut poly cord to desired length (you'll lose several inches for the knots, but gain additional length from the handle)
2) Cut MIL-SPEC nylon grosgrain ribbon to desired length for your leash handle/loop
3) Cut an additional ~4" piece of MIL-SPEC nylon grosgrain ribbon
4) Place the 4" piece of grosgrain ribbon at the end of the leash handle piece for reinforcement
5) Loop ~2" of grosgrain ribbon back on itself, including the reinforcement
6) Loop the other end of the ribbon back around and terminate ~1/4" from the end
7) Secure the ribbon in this position with Gutermann MARA 70 thread, being sure to leave a reinforced opening at the end for the poly cord to pass through
8) Run the end of the poly cord through the opening left in the leash handle; tie off with a bowline knot
9) Use a bowline knot to tie the other end of the poly to a lightweight carabiner; or, for ultimate weight savings, you can make a bowline with a several inch loop and then use that loop to tie your new leash to the d-ring on your pet's collar
*13-gram weight listed includes the use of an Ozark Trail 6cm carabiner