We understand that being comfortable is not only about what you see. What you wear as a base layer changes everything. Here at BIG BILL, we get that. The importance of the layering system is to allow yourself to safely regulate your body temperature during different levels of activity and different weather. The multi-layered system is a way of using what you have of clothes, putting them together, combining them, to use them in a system that will allow you to do all activities in all types of weather. Combining a base layer with an outer shell caused clothing systems to exhibit better water vapor permeability and less moisture accumulation. Shop BIG BILL Base layers as they are just as important as any other gear you wear to keep you comfortable all day.