British Standard (BS) chain refers to roller chains manufactured according to ISO 606 B, BS 228, and DIN 8187 European standards.
These chains are dimensionally different from American National Standards Institute (ANSI) chains and require compatible BS sprockets.
These chains are very similar in appearance and size to the ANSI chain series 35 through 160, but will not correctly interface with ANSI sprockets. Power-Link Catalog