BSM - British Standard Milk, also known as Milk or RJT fittings, were made for the milk industry. BSM unions are a hygienic coupling comprising of a stainless steel nut, liner, male part and o-ring (standard seals are EPDM, however other materials are available). Flat Faced BSM unions have flat seals and liners which gives a cleaner flush finish. Also available for capping off males are blank nuts and blank caps. If you want to reduce from one size line down to a smaller size we have machined or pressed reducing liners available. BSM aluminium spanners are used to open or tighten the union.