The DeWalt 5140209-78 Pressure Washer Piston helps generate the pressure needed for effective cleaning performance. This piston is a key pump component that moves back and forth within the pressure washer pump, creating the force required to draw in and compress water before it is discharged at high pressure. By supporting consistent water flow and pressure generation, it contributes ... https://www.wholetoolbox.com/dewalt-5140209-78-pressure-washer-piston