The rolling pin is hollow and therefore light and easy to work with, and at one end there is a large opening that allows the rolling pin to be filled with liquid and closed in an airtight manner without fear of leaks. The rolling pin can be filled with cold water to cool the dough while working with it, or with hot water to help thaw it, and in general can be filled if more weight is needed for rolling. You can use a rolling pin as it is for flat flattening, or with the adapters that allow flattening to a thickness of 3 mm or 6 mm, and also function as cookie cutters! The holes in the handle function as a window to see the side of the filler. The total volume of the rolling pin body is 1.4 liters. However, with cold water the volume is limited to 1.2 liters as the water expands in the freezer. See the markings on the product. The adapters for the rolling pin can be purchased separately.