A simple, handkerchief-like product, the Buff is a surprisingly versatile tube of fabric. After more than a decade of dedicated wear, from hot days to winter’s depths, I am a convert to the headwear.

Sometimes the simplest ideas can lead to the most useful products. Such is the case with the Buff, a versatile piece of equipment that has become a nearly essential piece of gear in the outdoor world.

Surely you’ve seen them on “Survivor,” the reality TV show whose contestants wore these simple,versatile garments to identify their tribes. They are products made by Buff, tubular bandanas made of ...