As per current World Athletics rules, javelins used in senior men’s competitions need to weigh at least 800 grams and measure between 2.6m and 2.7m. For women, the minimum weight needs to be 600 grams while length of javelin can be between 2.2m and 2.3m. Neeraj Chopra will feature in men's javelin final at Paris Olympics on August 8.