The PR1 range offers primary barricade override, which means that the key always dominates the internal turnpull, allowing staff permanent access. This facility is provided by a unique and patented mechanism within the lockcase itself. This avoids the need for a clutch cylinder, which can slip under side pressure, or a geared cylinder, which can allow service users to lock others in their rooms. It also allows a flexibilty in the selection of locking cylinders so that an existing master suite might be retained. Within PR1 is a full range of function options which should allow for all eventualities of door function within a mental health environment.