The MTS cylinder provides superior non-rotating accuracy and linear stability in a compact package. Traditional non-rotating cylinders typically can only hold position to within 0.5° and have inherent sealing problems. Integrating a ball spline as the rod bearing, this cylinder approximates the non-rotational accuracy of a guided cylinder without the added space requirements of external guide rods. In addition, a special rod seal design limits leakage to the equivalent of a round piston rod seal. An optional end lock retains the rod in the retracted position even in the event of loss of air pressure for added safety. Mounting can be done from four precisely machined faces with parallelism of less than 0.1mm.