You can roll groove a lot of pipe in a wide range of diameters with this model because the operator merely pushes a button to get the job done. Six easily interchanged Top and Bottom Rollers give Model 2021 the versatility to meet virtually any piping system requirement. The self-contained hydraulic system provides up to 16,000 psi pressure at the point of roll grooving. Hydraulic pressure is adjustable to provide optimum grooving efficiency for all diameters and wall thicknesses within the machine's range. Model 2021 is shipped completely assembled with Top and Bottom Rollers 4" through 6" installed on machine.