1) Shell. The shell is your first
line of defense against the elements, and must protect your body from
wind, rain and snow. At the same time, the shell must be
breathable - i.e., it must allow moisture to escape
through the fabric. Otherwise, you would quickly overheat or become
saturated in your own perspiration. Gore-Tex is perhaps the
best known fabric that is both waterproof and
a) Hard Shells.
Hard-faced shells such as those lined with Gore-Tex are usually both windproof and
waterproof. They are normally worn over an insulation layer
(the mid-layer) and the base layer to seal out the elements.
b) Soft Shells. Soft shells are hybrid shells that combine wind and water
resistance, breathability and light insulation. Many also
stretch for comfort and are made of "quiet" fabrics. Soft shells
are ideal for moderate fall and winter conditions, but
not fully waterproof. The appeal of the soft shell is its
versatility - it can serve as either a shell or mid-layer (or
2) Mid-Layer. The mid-layer
provides insulation - i.e., it traps your body's heat to give you
warmth. Popular mid-layers include fleece, wool, down and
Primaloft. As with the shell, the mid-layer must also "breathe"
efficiently. In mild, dry weather, you can do without a shell
jacket, and a mid-layer jacket or pullover can be your outer layer.
3) Base-layer. Simply put,
the base layer is clothing that comes in direct contact with your body,
including your underwear and T-shirt. An effective base layer must wick moisture away from your body so that it can eventually
escape through your mid-layer and shell. Synthetic fabrics or blends (such as polyester and nylon) and wool are much better at this task than cotton.