VTH series declutchable manual gear override features compact size and smooth operation generating a wide torque range from 100Nm to 4200Nm with labour-saving input torque from 20Nm to 50Nm. The series adopts new type of worm gearing and vortex rod drive mechanism, integrating up-to-date technology and material of declutchable gear override, based on extensive experience in site installation and product application, mainly dedicated to opening 90°stroke switch valves such as ball valve, plug valve, butterfly valve, and assisting pneumatic and electric actuators to guarantee opening and closing pipes.