Using proper operating practices, the load and arbor will always be balanced. However, when counterweight sets are not properly balanced, the operator can lose control of the set allowing it to “run away” — possibly causing damage or injury. The SureLock rope lock incorporates a load sensing mechanism, and can tell if a set is more than 50 lbs. out of balance. If the set is out of balance, the SureLock cannot be opened, preventing runaways.