The Hunter Safety System Lifeline System with Two Carabiners allows two hunters to be attached to the same lifeline for treestand safety. Reflective material makes it easy to find your stand in low-light conditions. Two sturdy carabiners. Cowbell sound dampener. A Video Public Service Announcement from the TREESTAND MANUFACTURERS ASSOCIATION Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Treestand Lifelines.