A roll cage is not just steel tubing welded together. It must be designed to hold the weight of the vehicle should it roll over or land upside down. A basic roll bar usually has 4 points of contact with the vehicle chassis. A typical roll cage may be an 8-point or more design. In many cases a roll cage designed for a particular car or truck may be purchased from a professional roll cage manufacturer. Kits are available which are easier to transport and must be welded together inside the vehicle. 