The gi is typically composed of a heavy cotton jacket, reinforced drawstring trousers, and a belt which communicates rank. According to article 8 of IBJJF rules, the best bjj grey gi must be constructed of cotton or similar material and be in good condition. The material may not be excessively thick or hard to the point where it will obstruct the opponent. Traditionally, gi pants are made of a sturdy cotton canvas, or denim with reinforced seams/knees. Tough and lightweight materials have started to become more popular in recent years as cooler hot weather gas have become more popular. It is common in tournaments to see competitors wearing rips top pants with a standard cotton gi top.