Kydex

Kydex, invented in 1965, is a line of thermoplastic acrylic-polyvinyl chloride materials which gives the plastic rigidity. It also can be molded into various shapes. Kydex combines the properties of the acrylic (rigidity and formability) and the polyvinyl chloride (durability and chemical resistance) components. It has a wide variety of applications, most notably for firearm holsters and sheaths. 

Kydex was first used as a holster material in 1972 by Chicago FBI agent Bill Rogers. Holsters made of this material are lightweight and durable. Demand for his product increased rapidly, and Rogers took a three-year leave from the FBI to make holsters. In 1973, he started the Rogers Holster Co., later purchased by Safariland in 1985.