① Zero leakage sealing in bi-directional and air tight test.

② Straight line flow characteristics. Optimum regulating performance.

③ Convey slurry, miniumu liquid left in the pipe, low flow resistance, rapid open-close,
     frequent operation.

④ Various material selection suits to various working medium and working conditions.

⑤ Easy dismantle and maintenance. Suitalbe for both vertical and horizontal installation