The most common and popular product in soft body armor is a fibrous product called Kevlar. It is manufactured by Du Pont. First developed in the sixties, it has been improved upon over the years. Kevlar is 5 times stronger than a piece of steel the same weight. Alternatives to Kevlar include Vectran, which is supposedly twice as strong as Kevlar. Biosteel is a genetically engineered fiber made from the same components as spider silk. Ceramics and polyethylene plastics are found in some types of body armor. For the higher levels of protection, plates of steel are used. These are very heavy and cumbersome, but are necessarily in the most dangerous situations.