Features: 1. Airtight sealing device, outdoor application is available. 2. Unique sealing ring design, it can perform good dust protection to avoid the dust permeate into housing body along with the shaft. 3. The torque force is adjustable. 4. The performance of torsion is stable and reliable. 5. If the rotary paddle bears an extra overload, the motor will be appeared slide to prevent the inside mechanism damaged. 6. It is rationally designed, the inside mechanisms are easily tore down for checking, maintenance and replacement. It doesn¡¦t necessary to remove the complete set from the tank. 7. Very suitable for small tank and material of low density