By offering 2 center D rings on a floating bridge gives the climber the option of attaching their climb line to 2 separate points. By attaching to 2 points, the climber can terminate their climb line to one D ring and their split tail to the other. This helps keep the climb line and attachments organized while also giving the climber the ability to spread the legs of climb line and work through them. Working through the legs offers stability and maneuverability.