This 1-1/2” inch 3 in 1 Rabbet Plane has an adjustable mouth. Shims are provided to open or close the mouth opening. Removing the front converts it into a Chisel Plane. This is a high precision tool capable of shaving extremely thin shavings with an appropriately sharpened blade. Perfect for removing hard to reach corner material and capable of producing very clean joinery in the right hands.