Includes leg and butterfly attachments. The resistance is created by the Isokinetic Device at the base of the machine. Within the Isokinetic Device there are two spring-loaded brakes, which ride within a smooth drum pressing against the sides. As you work, centrifugal force pushes the brakes against the drum to create resistance. The harder you puch, the more resistance is generated. Therefore, you never have to adjust the machine. It adjusts for you. There are three basic levels of resistance, which is determined by the number of pulleys that the cord is routed over. Making these adjustments is very easy. Each of these levels adjusts to the amount of force that you provide. I am asking $150.00. Unit is located in Flagstaff. Buyer responsible for delivery arrangements.