Ive been thinking about a wrist sheath for throwing knives so that when u flick ur wrist a knife either springs into ur hand or slips. Another use for the springing wrist sheath would be for self defense. Put ur hand on ur attacker’s neck flick ur wrist and a knife shoots out. It would only work if u knew where ur attacker’s arteries were and it would help if u had incapacitated them.