A single hook sex swing has a center hook and a bar which supports all of the necessary parts like the seat, back rest and stirrups. A dual hook swing, like the Screamer Dual Hook Sex Swing, has 2 mounts which allows the top to be open, leaving more room and allowing for more sexual positions. In addition, a dual hook sex swing enables you to adjust and move around the parts when, with most single hook swings, the parts stay in one spot.