Filling filters and tank filler necks with breathers from the SMBT series made of metal/steel for mounting on hydraulic tanks and containers. Allows permanent venting while protecting against contamination entering the system. Cap diameter either 47 or 80 mm. Version with male thread BSP or NPT for screwing in. With high-quality STAUFF zinc/nickel coating. Options, accessories and spare parts such as pressurisation, filling screens, dipsticks, air filter elements, adaptors, adaptor sets.