DT Fastener, as a professional structural nuts supplier, offers quality BS 4395-1 structure nuts at great prices. The BS standard is a British standard formulated by the British Standards Institution (BSI). BSI is an unofficial institution with a high reputation internationally. It was established in 1901 and is the world's earliest national standardization institution. It is not controlled by the government but has strong support from the government. BSI develops and revises British Standards and promotes their implementation.