Great question. Plaid has been used for western shirts because, traditionally, plaid was made out of flannel or wool which provided warmth and could protect cowboys against the elements. This warmth and comfort was extremely important since cowboys didn't often wear coats, since coats restricted mobility. 

Simple! They were easy to do up with one hand, which was important since a cowboy’s other hand would be holding the reins. 

The cowboy shirt is an iconic piece of western clothing and the long sleeves serve a very practical purpose: they protect the cowboys arms against brush, thistles and sun. 

Again, the design of this classic piece of western clothing is purely practical (although it does look great too). Cowboy shirts are fitted—as opposed to loose and boxy—to prevent the shirt from snagging on limbs or brush.

Cowboys need a thicker, long-wearing material to resist scratches from bushes, a material that can get wet then dry out in the sun without shrinking.

The first commercial-quantity denim manufacturer is generally considered to be Levi's who created the 5-pocket style including a small coin pocket. Levi Strauss knew about the heavy twill cotton material made famous in Nimes, France and in French, "from Nimes" can be translated into "de Nimes", or denim.

Denim jeans now come in many styles, but for cowboys a boot cut is needed where the width at the bottom of the leg will fit over a cowboy boot. Traditional styles, especially in the US, are starched. Starching can make the jeans stiff until work in, but also resist dust and dirt. 

Traditional styles have roominess needed for flexibility and sit at the waist. Now, slim fit styles, high-waist and low-waist options, not to mention dark and ligther washes and just about every wash in between, are all popular.

Over the decades Wrangler became closely associated with cowboys and rodeos, and Wrangler makes all these styles available, and Wei's stocks almost all of them.

Modern jean styles may include 1-2% spandex or other stretchy material to make the jeans even more comfortable. Typically jeans are 98-100% cotton but some styles include polyester in the material.  Quality cowboy jeans, like the ones we have, are not only stylish, but they’re rough and rugged and ready to ride. 

Oilskin is traditionally heavy cotton clothing, made waterproof with oil and sometimes linseed oil. Oilskin is wet weather wear, and is often made into clothing styles that enhance water resistance, such as high-collar coats.

Oilskin is not in the same waterproof category as rubber, or hip waders for fishing, but the wearer will generally stay quite dry in bad storms unless submerged.

Oilskins are found in many Australian styles at Wei's, including the Australian Outback collection.