Filter Tube BUFF®: Keeping ourselves and families safe and healthy has become a shared concern around the world. The BUFF® Filter Tube is reusable and features a 3-layer replaceable filter system in a washable multifunctional tubular made from recycled microfiber. Ergonomic neckwear design to be comfortable all day. Certified filters provide 98% bacterial filtration efficiency meeting the performance requirements of Bacterial Filtration Efficiency and Breathability of the harmonized European standard EN 14683:2019 for surgical masks.