Edelrid Smart-Belay Systems. Active safety for genuine climbing adventures: Smart belay technology is based on a system of communicating interconnected carabiners. If one of the carabiners is unlocked or has been detached from the main safety line the other carabiner stays locked until its counterpart has been safely attached to the cable again. Unintentionally detaching both carabiners from the lifeline, e.g. during the transition between two climbing parcourses, is therefore impossible.