This heavy-duty lifter model holder is specially designed for larger suction cups like Pro lifter 20. With these larger suction cups, the seam setter can grip stone surfaces tighter, so that the working performance can also be strengthened. These advanced suction cups are also advantaged by their wonderful performance even on rough stone materials: the supporting seal grants the cup a consistently strong grip both on flat or rough surfaces. The maximum capacity of each cup is 170kg. The position of the two cups is changeable by manually adjusting the balance slider between them, and the four rotary knobs can help to level the surface. This device makes great use of the two suction cups' grip, which enables it to hold tight on stone countertops to improve the seam-joining effect. Plus, aluminum bars and ratchets also reduce the device's weight, guaranteeing a long life and of it.