Reusable filter 725 p3. designed to protect against solid and liquid particles, including bacteria and viruses. manufactured from high-density polyethylene, black color, featuring an r marking (reusable filter). features a standard din en 148-1 (rd40) thread connection, compatible with climax full face masks 731-s, 731-c, 741 and equipment with normalized en 148-1 connection. standard en 143:2021