2″ is ground rock used as a base layer for projects. We do not manufacture 3” Minus and recommend 2” minus. We find that the 2” minus is much easier to work with and grade. Often the base layer will remain through a construction project without fine gravel on the surface, which offers a better driving surface for temporary traffic. Some contractors offer a 3” minus or call it a Granular B Type II. This material will perform the same, but is more difficult to grade and the driving surface is not as desirable as a 2” minus. Although we do manufacture 4” minus, we use 2” minus ourselves 99% of the time when constructing a base layer, and we recommend the same.