Like an underappreciated executive assistant—the glue that holds everything together—the importance of thread selection—often the weakest link in a sewn product—is frequently overlooked. This is especially true for fabric that is exposed to the elements and the sun, as UV rays can cause the thread to rot as shown above. PTFE (polytetrafluorethylene) thread, made from Teflon, is undaunted by the sun and other environmental foes, which is why it is known as a lifetime thread and why we use it on every stitch of our bags.