It consists of housing, side door, oil-cylinder, cylinder cover, piston, piston rod, locking-up shaft, sealing parts and ram. Cl It consists of housing, side door, oil-cylinder, cylinder cover, piston, piston rod, locking-up shaft, sealing parts and ram. Close or open the ram by pushing piston and piston rod through hydraulic pressure. So the well can be controlled. Single-ram BOP