Ring knife is a common alias used to describe Defender Ring.
The term "ring knife" describes Defender Ring very well; a person wears a jewelry ring around her finger that has a knife attached to it for self-defense purposes.
Why a Ring?
A knife can be affixed to many objects for self-defense purposes. There are household kitchen knives, folding pocket knives, and even smaller throwing knives. Each has advantages and disadvantages, but we chose a jewelry ring knife for the following reasons:
The Practicality of Jewelry
Women wear jewelry every day. In order to provide a practical self-defense option for women, what better way than to combine a knife with an item a woman can wear regularly whether she's jogging in the park or out to dinner with friends.
Accessibility of Rings
Jewelry rings are practically at your fingertips. You don't have to look at your ring to know where it is at all times. Designing a self-defense product that has a knife literally at a woman's fingertips gives her quick and immediate accessibility.