Body-armor designers have been working to close the gap between performance and comfort. The gap closed significantly with the introduction of a strong, lightweight fiber called Kevlar in 1965. Since that time, fiber manufacturers and body-armor designers have developed new fibers and fine-tuned weaving, cutting, and design techniques to make armor thinner, lighter, more concealable, more flexible, and more resistant against a greater range of increasingly powerful threats. The latest entrant to the fiber market is Zylon, a cutting-edge fabric with impressive tensile strength, thermal stability, and flexibility. Other new developments in the field include multi-threat armor that can defeat both ballistic and pointed and edged blades; microencapsulants that cool the wearer and regulate the temperature of the body armor; design modifications that allow for almost unlimited sizes and shapes in body armor, which can be computer "morphed" to fit the individual; and better designs and fabrics in K-9 body armor. In September 2000, the National Institute of Justice (NIJ) issued NIJ Standard-0101.04, Ballistic Resistance of Personal Body Armor, the first revision of the standard in 13 years. Testing under the revised standard was begun in fall 2000. The revised standard reflects the actual threat to law enforcement officers from ammunition and weapons on the street today.