The size, shape, minimum weight, and centre of gravity of the javelin are all defined by IAAF(WA) rules! Mountainsports Javelin 800 grams. Durable, stiff, and affordable, the Javelin is made with high quality aircraft aluminum. Each implement is designed, tested, and produced with the utmost attention to quality control and advanced production. Presenting the all new Mountainsports javelins. This product is the result of more than 40 years of sweat equity and innovation.