The RIGGER ENGINEERING liner wiper plug is designed to be run in tandem with a drill pipe dart to displace excess cement in the liner and to maintain separation of mud from the cement. After the required volume of cement is pumped down around the liner the rubber drill pipe dart is pumped down from a cement or plug dropping head. The rubber liner wiper plug is held in place below the cup mandrel or stinger via a shear pin or shear screw adapter. The drill pipe dart seats itself in a landing collar at the top of the wiper plug. Additional pressure shears the pins or screws, allowing both plugs to travel down the liner as a single unit, now wiping cement from the liner wall. This unit lands in a float collar or goes to the bottom of the well if no float collar is used. All plugs and landing collars are made of drillable materials for easy drill out later. Rigger Engineering offers both a standard liner wiper plug and a latch-in liner wiper plug.