Abstract. The PREMO standard, Presentation Environment for Multimedia Objects, is a major new standard under development within ISO/IEC. It addresses the creation of, presentation of, and interaction with all forms of information using single or multiple media. In this paper we give a formal LOTOS specification, amenable to automatic verification, of the PREMO synchronisable object, which is one of the central parts of the standard. Various design options are investigated by a combination of constraint oriented specification and model checking. This shows the usefulness of formal specification and automatic verification during the design phase of an international standard.