Bulletproof jackets were being manufactured with ballistic nylon material till the 1970s. In 1965, a compound — poly- parphenyleneterephthalamide – was invented with the brand name Kevlar. This is a liquid polymer which can be spun into fibre and woven into cloth. Kevlar was developed for tyres and, later, for ropes, gaskets and various parts of planes and boats. The efficacy of the material led to its usage for the manufacture of bulletproof jackets. Another product with the brand name Spectra was developed in 1989 as a competitor for Kevlar. Spectra is a polyethylene fibre developed as a sail cloth and, later, used to make stronger and lighter non-woven material for bulletproof jackets.