Aspect oriented programming promotes the separation of the different aspects of a system into their natural form. Synchronisation is an important aspect of concurrent object-oriented systems, but treating synchronisation as a single monolithic aspect leads to inflexibility and limited possibilities for reuse. We suggest that synchronisation has a number of different aspects, and introduce the synchronisation rings model which allows the aspects of a synchronised object to be specified independently. By separating the different aspects of synchronisation we can provide flexible, generic implementations of common synchronisation constraints, which can be re-used in many different contexts.