Karambit - Indonesian self-defence knife
The karambit is a small knife with a curved blade and handle, ending in a circle into which a finger is inserted. It was first used by the Minangkabau people, who lived in West Sumatra, and the shape of the knife is said to have been inspired by the claws of large cats. It was initially used as an agricultural tool, but a modified karambit with a more strongly curved blade began to be used - in the Philippines, among others - also as a weapon. The karambit is considered to be the most effective tool for self-defence.
Video showing the capabilities of the Karambit knife: https://www.youtube.com/watch?v=vi7TPa1eQ8w
Specification: