This unit is made with a 3mm welded frame and uses a pneumatic jack to handle the load. The load may move in many weights and can work with a compressor. The seat and motion adjustment pins are easy to handle as well. The push buttons can help to control the weight and are located at the hands and feet and may be used without having to stop the exercises. This is a soft and quiet unit that is also accurate. Air compression in this unit keeps residual inertia from being a problem and will help to make the process of working out on an iron-based weight stack a little easier to manage.