The Apollo 55000-885 is a Multi Sensor which uses the Apollo XP95 analogue addressable protocol. This sensor has both an optical smoke and thermal sensing element all housed within one detector.
The Apollo 55000-885 XP95 Multi Sensor is an ideal detector to help reduce false alarms within a building. This is becuase it can be set up so that the fire alarm system will only go into a full fire state when the detector has sensed both smoke and an increase in temperature within the room in which the sensor is situated. Apollo 55000-885 sensors are often installed in hotel bedrooms as standard optical smoke sensors can respond to steam from ensuite bathrooms, whereas multi sensors are less likely to false alarm in this situation.