HNRX Auto Lock is part of the HNRX Extreme Suppression System; the lock is designed to be filled with water and frozen and will take 1-2 hours - depending on room temperature - to thaw you free. The beauty of this lock is that your Dominant partner can lock you up knowing you will become free within the next few hours. However, we do not recommend leaving a restrained sub locked up without on-going supervision, for safety reasons. Made from stainless steel, the locks have o-ring fixtures compatible with the HNRX Extreme Suppression System. 10 Year Punishment Guarantee.