The original TDI series of knives changed many law enforcement officers’ idea of what an edged backup weapon could be. With input from tactical knifemaker Rick Hinderer, these models are gonna change all those minds all over again! The Original TDI Knife was designed by John Benner, founder of Tactical Defense Institute. A former Police Lieutenant, Drug Task Force Coordinator, and SWAT Team Tactical Field Commander, Benner has more than 30 years' experience in the law enforcement field. He has developed courses for raid tactics, defensive tactics and knife programs that are currently taught to law enforcement, military and civilian groups.