Safety hook knife
A safety hook knife (also known simply as a safety hook) is a very sharp-bladed instrument with the blade protected on the inside of the hook. They are a useful item of bondage safety equipment for cutting people out of bondage fast, in cases of personal or situational emergency (such as seizures or fire).
The more useful hooks have finger-grips or finger holes on them for a secure hand hold.
For emergency cutting of ropes, these safety hooks are safer than an open blade, which in emergency situations can be a danger in themselves. Safety hooks can also be quicker than EMT scissors or shears and may be more versatile. It is hard to harm someone with a safety hook unless you try, in which case they can be dangerous to fingers, toes and ears.
A good safety hook knife can cut through 3/8" poly/nylon solid braid in one slice and can even slice through thick leather with ease. They are available from some bondage shops and also from emergency supplies retailers.