ESD Brushes are ideal for removing dust, dirt and left over materials from printed circuit boards (PCB) and other static sensitive components. Generally speaking, once the conductive yarn is added to the bristles, it neutralizes the possibility of static build up caused by the natural hair. Synthetic bristles can easily become charged with static in standard humidity conditions. Natural hair usually builds static in areas of low humidity, but due to the conductive fibers in our brushes, this problem does not take effect. Firm bristles measures 1/4" diameter by 0.59" height. Made in America.