Keep your sub trapped under ice!
This lock is more sadistic than it appears. Sure your sub is on a time release lock meaning they will eventually be free but what they don't think about is the cold water that drips on them the entire time they await their freedom!
The small lock can last anywhere between 15 to 40 minutes and the larger one 40 minutes and 2.5 hours depending on how cold the room is and how much water you put in the cylinder.
If you're into self bondage, this comes in very handy since you can never really tie up that last restraint. Use this and you're restrained for quite some time! You can even make the ice lock last longer with the included neoprene insulator.