Some member brokerage firms have large floor staffs. In practice, all the staff from the same brokerage firm wear the same color jackets, which sometimes also bear the company name or logo, in much the same manner that sports teams wear uniforms. This helps the staff find each other on the crowded trading floor. The jackets also help for easy recognition during active trading. Independent traders often wear trading jackets in colors of their own choosing or they sometimes wear the same color of jacket as that of the member firm that clears their trades.
Trading is conducted through a public auction system.
Through open outcry, the trader shouts the quantity of the commodity he is buying or selling, and the corresponding price he wants. The hand signals are a specialized sign language which clarify the traders verbal bids and offers, particularly when trading is highly active. Each finger held vertically indicates quantity. Fingers extended horizontally express the price at which the bid or offer is made. The open outcry is the primary market.