1) Anti-rotation mechanism protects the closing sleeve rom damage while drilling out the opening and losing seats.

  2) No fluid trapping while opening and closing the ports. 

3) All internal parts are made of easily drillable material. 

4) All accessories are made of easily drillable rubber and aluminum alloy. 

5) The free-fall opening plug is filled with weighted material to reduce free-fall time. 

6) The first-stage wiper plug is used for bumping during the first stage cementation.