The DSTB is part of the Instrument Collection and, like every other model from Arnold & Son, features an in-house mechanical movement. The true beat seconds is a traditional complication of Arnold & Son, and this watch pays tribute to the watches produced by John Arnold during the second half of his career, when he and his son were the first to develop marine chronometers that could be produced in quantity at reasonable prices. Those technically superior, widely distributed chronometers reflected Arnold & Son's commitment to exceptional precision and solved the problem of determining longitude at sea.