Portable handheld chainsaws are often equipped with an adjustable backing board, also known as an adjustable plug board. Used as a stand when the band saw is cutting vertically (90 degrees perpendicular to the material being cut). Turn the screw to pull the backing out and extend it against the material. This makes the cutting operation more stable.

Adjusting the protrusion of stopper plate
In the ordinary operation, protrude the stopper plate to the A side fully.When the stopper plate strikes against the obstacles like a wall or the like at the finishing of a cut, loosen two screws and slide it to the B side in the figure.After sliding the stopper plate, secure it by tightening two screws firmly.