ORB-OP-52027-APO Orbis I.S. Optical Smoke DetectorORB OP 52027 APO Orbis I. S. Optical Smoke Detector The Orbis I. S. Optical Smoke Detector works using the light scatter principle and is ideal for applications where slow burning or smouldering fires are likely. Key Features: Reduces false alarms Recommended for early warning of fire in most areas Improved sensitivity to black smoke Compensation for slow changes in sensitivity Algorithms for reliability of alarm About Apollo Orbis: Quicker and easier