Take your Self Retracting Lifeline and hold it in your hands. Slowly pull the cable or webbing out. If you do this slowly enough, it continues to play out until it reaches its full length. Now, let it retract. This time, snap the cable or webbing out. If you pull hard enough you will see it lock into place. Congratulations, you’ve just demonstrated how SRLs work without having to toss somebody over the side of a building!